https://hades.mech.northwestern.edu//index.php?action=history&feed=atom&title=NU32v2%3A_Digital_I%2FO_Assembly_CodeNU32v2: Digital I/O Assembly Code - Revision history2026-06-18T23:58:41ZRevision history for this page on the wikiMediaWiki 1.43.8https://hades.mech.northwestern.edu//index.php?title=NU32v2:_Digital_I/O_Assembly_Code&diff=23704&oldid=prevLynch at 11:22, 16 January 20162016-01-16T11:22:29Z<p></p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
<col class="diff-marker" />
<col class="diff-content" />
<col class="diff-marker" />
<col class="diff-content" />
<tr class="diff-title" lang="en">
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 06:22, 16 January 2016</td>
</tr><tr>
<td colspan="2" class="diff-lineno">Line 1:</td>
<td colspan="2" class="diff-lineno">Line 1:</td>
</tr>
<tr>
<td colspan="2" class="diff-empty diff-side-deleted"></td>
<td class="diff-marker" data-marker="+"></td>
<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>'''THIS PAGE REFERS TO A PRE-RELEASE VERSION OF THE NU32 PIC32 DEVELOPMENT BOARD. FOR INFORMATION, SAMPLE CODE, AND VIDEOS RELATED TO THE PRODUCTION VERSION (2016 AND LATER), AND TO THE CORRESPONDING BOOK "EMBEDDED COMPUTING AND MECHATRONICS WITH THE PIC32 MICROCONTROLLER," VISIT [[NU32|THE NU32 PAGE]].'''</div></td>
</tr>
<tr>
<td colspan="2" class="diff-empty diff-side-deleted"></td>
<td class="diff-marker" data-marker="+"></td>
<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><br /></td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Let's say we called our source code digio.c. When we compile it, we find an "object code" file digio.o somewhere. I can "disassemble" this object code to see an assembly language version of the code. (You can either do this directly in the MPLAB IDE, or run the command-line functions pic32-nm or pic32-objdump with your .o file as the argument. These can be found in your C32 directory under "bin." For example, to produce the output below, I used <tt>pic32-objdump -D digio.o</tt>.) When we look at our disassembled code, we see a lot of stuff, including the block of code below. I added the comments beginning with //, since we don't know assembly language. </div></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Let's say we called our source code digio.c. When we compile it, we find an "object code" file digio.o somewhere. I can "disassemble" this object code to see an assembly language version of the code. (You can either do this directly in the MPLAB IDE, or run the command-line functions pic32-nm or pic32-objdump with your .o file as the argument. These can be found in your C32 directory under "bin." For example, to produce the output below, I used <tt>pic32-objdump -D digio.o</tt>.) When we look at our disassembled code, we see a lot of stuff, including the block of code below. I added the comments beginning with //, since we don't know assembly language. </div></td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
</tr>
</table>Lynchhttps://hades.mech.northwestern.edu//index.php?title=NU32v2:_Digital_I/O_Assembly_Code&diff=19897&oldid=prevLynch at 12:09, 26 January 20112011-01-26T12:09:17Z<p></p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
<col class="diff-marker" />
<col class="diff-content" />
<col class="diff-marker" />
<col class="diff-content" />
<tr class="diff-title" lang="en">
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 07:09, 26 January 2011</td>
</tr><tr>
<td colspan="2" class="diff-lineno">Line 23:</td>
<td colspan="2" class="diff-lineno">Line 23:</td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>I see 11 instructions in the loop, just less than my estimated 12 instructions. </div></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>I see 11 instructions in the loop, just less than my estimated 12 instructions. </div></td>
</tr>
<tr>
<td class="diff-marker" data-marker="−"></td>
<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><<del style="font-weight: bold; text-decoration: none;">1</del>-- Usually we have one assembly instruction per machine instruction (cycle), but sometimes an assembly instruction expands to more than one machine instruction. Is that what's happening here---there's an extra machine instruction we're not seeing? Or bad timing by me? Not sure. --></div></td>
<td class="diff-marker" data-marker="+"></td>
<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><<ins style="font-weight: bold; text-decoration: none;">!</ins>-- Usually we have one assembly instruction per machine instruction (cycle), but sometimes an assembly instruction expands to more than one machine instruction. Is that what's happening here---there's an extra machine instruction we're not seeing? Or bad timing by me? Not sure. --></div></td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Notice our use of the constant 10,000,000 in the code actually requires two assembly instructions to load the value into register v0: one for the most significant half-word (16 bits), and one for the least significant half-word. We have a limit of 32 bits total to specify the instruction (and some of them are used for the opcode and specifying the register). If we created a variable and assigned it the value 10,000,000, on the other hand, the entire word could be loaded with one lw instruction.</div></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Notice our use of the constant 10,000,000 in the code actually requires two assembly instructions to load the value into register v0: one for the most significant half-word (16 bits), and one for the least significant half-word. We have a limit of 32 bits total to specify the instruction (and some of them are used for the opcode and specifying the register). If we created a variable and assigned it the value 10,000,000, on the other hand, the entire word could be loaded with one lw instruction.</div></td>
</tr>
</table>Lynchhttps://hades.mech.northwestern.edu//index.php?title=NU32v2:_Digital_I/O_Assembly_Code&diff=19896&oldid=prevLynch at 12:09, 26 January 20112011-01-26T12:09:03Z<p></p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
<col class="diff-marker" />
<col class="diff-content" />
<col class="diff-marker" />
<col class="diff-content" />
<tr class="diff-title" lang="en">
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 07:09, 26 January 2011</td>
</tr><tr>
<td colspan="2" class="diff-lineno">Line 22:</td>
<td colspan="2" class="diff-lineno">Line 22:</td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>The first number in each row is the address of the instruction relative to the start of the program at 000. (Note that the instructions are each 4 bytes long, or 32 bits, so the address of each successive instruction is 4 bytes greater than the previous one.) The second number is the 32-bit instruction written in hexadecimal; the first several bits are for the instruction type, or "opcode," and the remaining bits are to specify registers, memory locations, values, etc., used by the instruction. The next column is the opcode in human-readable form, and the last column contains the human-readable form of the registers, memory locations, values, etc., used by the instruction.</div></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>The first number in each row is the address of the instruction relative to the start of the program at 000. (Note that the instructions are each 4 bytes long, or 32 bits, so the address of each successive instruction is 4 bytes greater than the previous one.) The second number is the 32-bit instruction written in hexadecimal; the first several bits are for the instruction type, or "opcode," and the remaining bits are to specify registers, memory locations, values, etc., used by the instruction. The next column is the opcode in human-readable form, and the last column contains the human-readable form of the registers, memory locations, values, etc., used by the instruction.</div></td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
</tr>
<tr>
<td class="diff-marker" data-marker="−"></td>
<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>I see 11 instructions in the loop, just less than my estimated 12 instructions. <del style="font-weight: bold; text-decoration: none;">Usually we have one assembly instruction per machine instruction (cycle), but sometimes an assembly instruction expands to more than one machine instruction. Is that what's happening here---there's an extra machine instruction we're not seeing? Or bad timing by me? Not sure.</del></div></td>
<td class="diff-marker" data-marker="+"></td>
<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>I see 11 instructions in the loop, just less than my estimated 12 instructions. </div></td>
</tr>
<tr>
<td colspan="2" class="diff-empty diff-side-deleted"></td>
<td class="diff-marker" data-marker="+"></td>
<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><1-- Usually we have one assembly instruction per machine instruction (cycle), but sometimes an assembly instruction expands to more than one machine instruction. Is that what's happening here---there's an extra machine instruction we're not seeing? Or bad timing by me? Not sure. --></div></td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Notice our use of the constant 10,000,000 in the code actually requires two assembly instructions to load the value into register v0: one for the most significant half-word (16 bits), and one for the least significant half-word. We have a limit of 32 bits total to specify the instruction (and some of them are used for the opcode and specifying the register). If we created a variable and assigned it the value 10,000,000, on the other hand, the entire word could be loaded with one lw instruction.</div></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Notice our use of the constant 10,000,000 in the code actually requires two assembly instructions to load the value into register v0: one for the most significant half-word (16 bits), and one for the least significant half-word. We have a limit of 32 bits total to specify the instruction (and some of them are used for the opcode and specifying the register). If we created a variable and assigned it the value 10,000,000, on the other hand, the entire word could be loaded with one lw instruction.</div></td>
</tr>
</table>Lynchhttps://hades.mech.northwestern.edu//index.php?title=NU32v2:_Digital_I/O_Assembly_Code&diff=19895&oldid=prevLynch at 12:08, 26 January 20112011-01-26T12:08:03Z<p></p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
<col class="diff-marker" />
<col class="diff-content" />
<col class="diff-marker" />
<col class="diff-content" />
<tr class="diff-title" lang="en">
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 07:08, 26 January 2011</td>
</tr><tr>
<td colspan="2" class="diff-lineno">Line 11:</td>
<td colspan="2" class="diff-lineno">Line 11:</td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> 364: 0043102a slt v0,v0,v1 // if v0 < v1, set v0 to 1, otherwise to 0</div></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> 364: 0043102a slt v0,v0,v1 // if v0 < v1, set v0 to 1, otherwise to 0</div></td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> 368: 1440ffe4 bnez v0,2fc <main+0x2fc> // if v0 is nonzero (i.e., 10 M <= i), exit "for" loop</div></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> 368: 1440ffe4 bnez v0,2fc <main+0x2fc> // if v0 is nonzero (i.e., 10 M <= i), exit "for" loop</div></td>
</tr>
<tr>
<td class="diff-marker" data-marker="−"></td>
<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div> 36c: 00000000 nop // no operation </div></td>
<td class="diff-marker" data-marker="+"></td>
<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> 36c: 00000000 nop // no operation<ins style="font-weight: bold; text-decoration: none;">;</ins> <ins style="font-weight: bold; text-decoration: none;">finish branching</ins></div></td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> 370: 8fc20010 lw v0,16(s8) // load i into v0</div></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> 370: 8fc20010 lw v0,16(s8) // load i into v0</div></td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> 374: 24420001 addiu v0,v0,1 // (unsigned integer) add 1 to v0</div></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> 374: 24420001 addiu v0,v0,1 // (unsigned integer) add 1 to v0</div></td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> 378: afc20010 sw v0,16(s8) // store v0 back to i</div></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> 378: afc20010 sw v0,16(s8) // store v0 back to i</div></td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> 37c: 1000fff6 b 358 <main+0x358> // go back to start of loop, instruction 358</div></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> 37c: 1000fff6 b 358 <main+0x358> // go back to start of loop, instruction 358</div></td>
</tr>
<tr>
<td class="diff-marker" data-marker="−"></td>
<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div> 380: 00000000 nop // no operation</div></td>
<td class="diff-marker" data-marker="+"></td>
<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> 380: 00000000 nop // no operation<ins style="font-weight: bold; text-decoration: none;">; finish branching</ins></div></td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div></pre></div></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div></pre></div></td>
</tr>
</table>Lynchhttps://hades.mech.northwestern.edu//index.php?title=NU32v2:_Digital_I/O_Assembly_Code&diff=19866&oldid=prevLynch at 09:28, 26 January 20112011-01-26T09:28:35Z<p></p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
<col class="diff-marker" />
<col class="diff-content" />
<col class="diff-marker" />
<col class="diff-content" />
<tr class="diff-title" lang="en">
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 04:28, 26 January 2011</td>
</tr><tr>
<td colspan="2" class="diff-lineno">Line 26:</td>
<td colspan="2" class="diff-lineno">Line 26:</td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Notice our use of the constant 10,000,000 in the code actually requires two assembly instructions to load the value into register v0: one for the most significant half-word (16 bits), and one for the least significant half-word. We have a limit of 32 bits total to specify the instruction (and some of them are used for the opcode and specifying the register). If we created a variable and assigned it the value 10,000,000, on the other hand, the entire word could be loaded with one lw instruction.</div></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Notice our use of the constant 10,000,000 in the code actually requires two assembly instructions to load the value into register v0: one for the most significant half-word (16 bits), and one for the least significant half-word. We have a limit of 32 bits total to specify the instruction (and some of them are used for the opcode and specifying the register). If we created a variable and assigned it the value 10,000,000, on the other hand, the entire word could be loaded with one lw instruction.</div></td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
</tr>
<tr>
<td class="diff-marker" data-marker="−"></td>
<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>If you're interested to learn more about assembly instruction sets, you can start with [http://en.wikipedia.org/wiki/MIPS_architecture http://en.wikipedia.org/wiki/MIPS_architecture], or the [[Media:MIPSInstructionReference.pdf|MIPS Instruction Set Reference]] or [[Media:MIPS-M4K-Core.pdf|MIPS32 M4K Core Software Reference]]. If you are writing C code that needs to be very time or memory efficient, you can include assembly commands directly in your C code using <tt>asm</tt>. As a simple example, the line <tt>asm("nop")</tt> will directly insert a nop in your compiled code. We will not go into assembly in more detail.</div></td>
<td class="diff-marker" data-marker="+"></td>
<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>If you're interested to learn more about assembly instruction sets, you can start with [http://en.wikipedia.org/wiki/MIPS_architecture http://en.wikipedia.org/wiki/MIPS_architecture], or the [[Media:MIPSInstructionReference.pdf|MIPS Instruction Set Reference]] or [[Media:MIPS-M4K-Core.pdf|MIPS32 M4K Core Software Reference]]. If you are writing C code that needs to be very time or memory efficient, you can include assembly commands directly in your C code using <tt>asm</tt>. As a simple example, the line <tt>asm("nop")</tt> will directly insert a nop in your compiled code.<ins style="font-weight: bold; text-decoration: none;"> (Though that specific example may not help with efficiency!)</ins> We will not go into assembly in more detail.</div></td>
</tr>
</table>Lynchhttps://hades.mech.northwestern.edu//index.php?title=NU32v2:_Digital_I/O_Assembly_Code&diff=19865&oldid=prevLynch at 09:28, 26 January 20112011-01-26T09:28:00Z<p></p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
<col class="diff-marker" />
<col class="diff-content" />
<col class="diff-marker" />
<col class="diff-content" />
<tr class="diff-title" lang="en">
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 04:28, 26 January 2011</td>
</tr><tr>
<td colspan="2" class="diff-lineno">Line 26:</td>
<td colspan="2" class="diff-lineno">Line 26:</td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Notice our use of the constant 10,000,000 in the code actually requires two assembly instructions to load the value into register v0: one for the most significant half-word (16 bits), and one for the least significant half-word. We have a limit of 32 bits total to specify the instruction (and some of them are used for the opcode and specifying the register). If we created a variable and assigned it the value 10,000,000, on the other hand, the entire word could be loaded with one lw instruction.</div></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Notice our use of the constant 10,000,000 in the code actually requires two assembly instructions to load the value into register v0: one for the most significant half-word (16 bits), and one for the least significant half-word. We have a limit of 32 bits total to specify the instruction (and some of them are used for the opcode and specifying the register). If we created a variable and assigned it the value 10,000,000, on the other hand, the entire word could be loaded with one lw instruction.</div></td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
</tr>
<tr>
<td class="diff-marker" data-marker="−"></td>
<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>If you're interested to learn more about assembly instruction sets, you can start with [http://en.wikipedia.org/wiki/MIPS_architecture http://en.wikipedia.org/wiki/MIPS_architecture], or the [[Media:MIPSInstructionReference.pdf|MIPS Instruction Set Reference]] or [[Media:MIPS-M4K-Core.pdf|MIPS32 M4K Core Software Reference]]. If you are writing code that needs to be very efficient, you can include assembly commands directly in your C code using <tt>asm</tt>. As a simple example, the line <tt>asm("nop")</tt> will directly insert a nop in your compiled code. We will not go into assembly in more detail.</div></td>
<td class="diff-marker" data-marker="+"></td>
<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>If you're interested to learn more about assembly instruction sets, you can start with [http://en.wikipedia.org/wiki/MIPS_architecture http://en.wikipedia.org/wiki/MIPS_architecture], or the [[Media:MIPSInstructionReference.pdf|MIPS Instruction Set Reference]] or [[Media:MIPS-M4K-Core.pdf|MIPS32 M4K Core Software Reference]]. If you are writing<ins style="font-weight: bold; text-decoration: none;"> C</ins> code that needs to be very<ins style="font-weight: bold; text-decoration: none;"> time or memory</ins> efficient, you can include assembly commands directly in your C code using <tt>asm</tt>. As a simple example, the line <tt>asm("nop")</tt> will directly insert a nop in your compiled code. We will not go into assembly in more detail.</div></td>
</tr>
</table>Lynchhttps://hades.mech.northwestern.edu//index.php?title=NU32v2:_Digital_I/O_Assembly_Code&diff=19864&oldid=prevLynch at 09:25, 26 January 20112011-01-26T09:25:02Z<p></p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
<col class="diff-marker" />
<col class="diff-content" />
<col class="diff-marker" />
<col class="diff-content" />
<tr class="diff-title" lang="en">
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 04:25, 26 January 2011</td>
</tr><tr>
<td colspan="2" class="diff-lineno">Line 20:</td>
<td colspan="2" class="diff-lineno">Line 20:</td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div></pre></div></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div></pre></div></td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
</tr>
<tr>
<td class="diff-marker" data-marker="−"></td>
<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>The first number in each row is the address of the <del style="font-weight: bold; text-decoration: none;">first</del> <del style="font-weight: bold; text-decoration: none;">byte</del> of each instruction. The second number is the 32-bit instruction written in hexadecimal; the first several bits are for the instruction type, or "opcode," and the remaining bits are to specify registers, memory locations, values, etc., used by the instruction. The next column is the opcode in human-readable form, and the last column contains the human-readable form of the registers, memory locations, values, etc., used by the instruction.</div></td>
<td class="diff-marker" data-marker="+"></td>
<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>The first number in each row is the address of the <ins style="font-weight: bold; text-decoration: none;">instruction</ins> <ins style="font-weight: bold; text-decoration: none;">relative to the start</ins> of<ins style="font-weight: bold; text-decoration: none;"> the program at 000. (Note that the instructions are</ins> each<ins style="font-weight: bold; text-decoration: none;"> 4 bytes long, or 32 bits, so the address of each successive</ins> instruction<ins style="font-weight: bold; text-decoration: none;"> is 4 bytes greater than the previous one</ins>.<ins style="font-weight: bold; text-decoration: none;">)</ins> The second number is the 32-bit instruction written in hexadecimal; the first several bits are for the instruction type, or "opcode," and the remaining bits are to specify registers, memory locations, values, etc., used by the instruction. The next column is the opcode in human-readable form, and the last column contains the human-readable form of the registers, memory locations, values, etc., used by the instruction.</div></td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
</tr>
<tr>
<td class="diff-marker" data-marker="−"></td>
<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>I see<del style="font-weight: bold; text-decoration: none;"> 10 or</del> 11 instructions in the loop, just less than my estimated 12 instructions. Usually we have one assembly instruction per machine instruction (cycle), but sometimes an assembly instruction expands to more than one machine instruction. Is that what's happening here---there's an extra machine instruction we're not seeing? Or bad timing by me? Not sure.</div></td>
<td class="diff-marker" data-marker="+"></td>
<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>I see 11 instructions in the loop, just less than my estimated 12 instructions. Usually we have one assembly instruction per machine instruction (cycle), but sometimes an assembly instruction expands to more than one machine instruction. Is that what's happening here---there's an extra machine instruction we're not seeing? Or bad timing by me? Not sure.</div></td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Notice our use of the constant 10,000,000 in the code actually requires two assembly instructions to load the value into register v0: one for the most significant half-word (16 bits), and one for the least significant half-word. We have a limit of 32 bits total to specify the instruction (and some of them are used for the opcode and specifying the register). If we created a variable and assigned it the value 10,000,000, on the other hand, the entire word could be loaded with one lw instruction.</div></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Notice our use of the constant 10,000,000 in the code actually requires two assembly instructions to load the value into register v0: one for the most significant half-word (16 bits), and one for the least significant half-word. We have a limit of 32 bits total to specify the instruction (and some of them are used for the opcode and specifying the register). If we created a variable and assigned it the value 10,000,000, on the other hand, the entire word could be loaded with one lw instruction.</div></td>
</tr>
</table>Lynchhttps://hades.mech.northwestern.edu//index.php?title=NU32v2:_Digital_I/O_Assembly_Code&diff=19833&oldid=prevLynch at 16:43, 25 January 20112011-01-25T16:43:18Z<p></p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
<col class="diff-marker" />
<col class="diff-content" />
<col class="diff-marker" />
<col class="diff-content" />
<tr class="diff-title" lang="en">
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 11:43, 25 January 2011</td>
</tr><tr>
<td colspan="2" class="diff-lineno">Line 26:</td>
<td colspan="2" class="diff-lineno">Line 26:</td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Notice our use of the constant 10,000,000 in the code actually requires two assembly instructions to load the value into register v0: one for the most significant half-word (16 bits), and one for the least significant half-word. We have a limit of 32 bits total to specify the instruction (and some of them are used for the opcode and specifying the register). If we created a variable and assigned it the value 10,000,000, on the other hand, the entire word could be loaded with one lw instruction.</div></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Notice our use of the constant 10,000,000 in the code actually requires two assembly instructions to load the value into register v0: one for the most significant half-word (16 bits), and one for the least significant half-word. We have a limit of 32 bits total to specify the instruction (and some of them are used for the opcode and specifying the register). If we created a variable and assigned it the value 10,000,000, on the other hand, the entire word could be loaded with one lw instruction.</div></td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
</tr>
<tr>
<td class="diff-marker" data-marker="−"></td>
<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>If you're interested to learn more about assembly instruction sets, you can start with [http://en.wikipedia.org/wiki/MIPS_architecture http://en.wikipedia.org/wiki/MIPS_architecture], or the [[Media:MIPSInstructionReference.pdf|MIPS Instruction Set Reference]] or [[Media:MIPS-M4K-Core.pdf|MIPS32 M4K Core Software Reference]]. If you are writing code that needs to be very efficient, you can include assembly commands directly in your C code using <tt>asm</tt>. As a simple example, the line <tt>asm("nop")<del style="font-weight: bold; text-decoration: none;">;</del></tt> will directly insert a nop in your compiled code. We will not go into assembly in more detail.</div></td>
<td class="diff-marker" data-marker="+"></td>
<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>If you're interested to learn more about assembly instruction sets, you can start with [http://en.wikipedia.org/wiki/MIPS_architecture http://en.wikipedia.org/wiki/MIPS_architecture], or the [[Media:MIPSInstructionReference.pdf|MIPS Instruction Set Reference]] or [[Media:MIPS-M4K-Core.pdf|MIPS32 M4K Core Software Reference]]. If you are writing code that needs to be very efficient, you can include assembly commands directly in your C code using <tt>asm</tt>. As a simple example, the line <tt>asm("nop")</tt> will directly insert a nop in your compiled code. We will not go into assembly in more detail.</div></td>
</tr>
</table>Lynchhttps://hades.mech.northwestern.edu//index.php?title=NU32v2:_Digital_I/O_Assembly_Code&diff=19832&oldid=prevLynch at 16:43, 25 January 20112011-01-25T16:43:01Z<p></p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
<col class="diff-marker" />
<col class="diff-content" />
<col class="diff-marker" />
<col class="diff-content" />
<tr class="diff-title" lang="en">
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 11:43, 25 January 2011</td>
</tr><tr>
<td colspan="2" class="diff-lineno">Line 26:</td>
<td colspan="2" class="diff-lineno">Line 26:</td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Notice our use of the constant 10,000,000 in the code actually requires two assembly instructions to load the value into register v0: one for the most significant half-word (16 bits), and one for the least significant half-word. We have a limit of 32 bits total to specify the instruction (and some of them are used for the opcode and specifying the register). If we created a variable and assigned it the value 10,000,000, on the other hand, the entire word could be loaded with one lw instruction.</div></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Notice our use of the constant 10,000,000 in the code actually requires two assembly instructions to load the value into register v0: one for the most significant half-word (16 bits), and one for the least significant half-word. We have a limit of 32 bits total to specify the instruction (and some of them are used for the opcode and specifying the register). If we created a variable and assigned it the value 10,000,000, on the other hand, the entire word could be loaded with one lw instruction.</div></td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
</tr>
<tr>
<td class="diff-marker" data-marker="−"></td>
<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>If you're interested to learn more about assembly instruction sets, you can start with [http://en.wikipedia.org/wiki/MIPS_architecture http://en.wikipedia.org/wiki/MIPS_architecture], or the [[Media:MIPSInstructionReference.pdf|MIPS Instruction Set Reference]] or [[Media:MIPS-M4K-Core.pdf|MIPS32 M4K Core Software Reference]]. If you are writing code that needs to be very efficient, you can include assembly commands directly in your C code using <tt>asm</<del style="font-weight: bold; text-decoration: none;">t</del>>. As a simple example, the line <tt>asm("nop");</tt> will directly insert a nop in your compiled code. We will not go into assembly in more detail.</div></td>
<td class="diff-marker" data-marker="+"></td>
<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>If you're interested to learn more about assembly instruction sets, you can start with [http://en.wikipedia.org/wiki/MIPS_architecture http://en.wikipedia.org/wiki/MIPS_architecture], or the [[Media:MIPSInstructionReference.pdf|MIPS Instruction Set Reference]] or [[Media:MIPS-M4K-Core.pdf|MIPS32 M4K Core Software Reference]]. If you are writing code that needs to be very efficient, you can include assembly commands directly in your C code using <tt>asm</<ins style="font-weight: bold; text-decoration: none;">tt</ins>>. As a simple example, the line <tt>asm("nop");</tt> will directly insert a nop in your compiled code. We will not go into assembly in more detail.</div></td>
</tr>
</table>Lynchhttps://hades.mech.northwestern.edu//index.php?title=NU32v2:_Digital_I/O_Assembly_Code&diff=19831&oldid=prevLynch at 16:42, 25 January 20112011-01-25T16:42:45Z<p></p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
<col class="diff-marker" />
<col class="diff-content" />
<col class="diff-marker" />
<col class="diff-content" />
<tr class="diff-title" lang="en">
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 11:42, 25 January 2011</td>
</tr><tr>
<td colspan="2" class="diff-lineno">Line 26:</td>
<td colspan="2" class="diff-lineno">Line 26:</td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Notice our use of the constant 10,000,000 in the code actually requires two assembly instructions to load the value into register v0: one for the most significant half-word (16 bits), and one for the least significant half-word. We have a limit of 32 bits total to specify the instruction (and some of them are used for the opcode and specifying the register). If we created a variable and assigned it the value 10,000,000, on the other hand, the entire word could be loaded with one lw instruction.</div></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Notice our use of the constant 10,000,000 in the code actually requires two assembly instructions to load the value into register v0: one for the most significant half-word (16 bits), and one for the least significant half-word. We have a limit of 32 bits total to specify the instruction (and some of them are used for the opcode and specifying the register). If we created a variable and assigned it the value 10,000,000, on the other hand, the entire word could be loaded with one lw instruction.</div></td>
</tr>
<tr>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
<td class="diff-marker"></td>
<td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br /></td>
</tr>
<tr>
<td class="diff-marker" data-marker="−"></td>
<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>If you're interested to learn more about assembly instruction sets, you can start with [http://en.wikipedia.org/wiki/MIPS_architecture http://en.wikipedia.org/wiki/MIPS_architecture], or the [[Media:MIPSInstructionReference.pdf|MIPS Instruction Set Reference]] or [[Media:MIPS-M4K-Core.pdf|MIPS32 M4K Core Software Reference]], <del style="font-weight: bold; text-decoration: none;">but</del> <del style="font-weight: bold; text-decoration: none;">we</del> <del style="font-weight: bold; text-decoration: none;">won'</del>t go into assembly in more detail.</div></td>
<td class="diff-marker" data-marker="+"></td>
<td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>If you're interested to learn more about assembly instruction sets, you can start with [http://en.wikipedia.org/wiki/MIPS_architecture http://en.wikipedia.org/wiki/MIPS_architecture], or the [[Media:MIPSInstructionReference.pdf|MIPS Instruction Set Reference]] or [[Media:MIPS-M4K-Core.pdf|MIPS32 M4K Core Software Reference]]<ins style="font-weight: bold; text-decoration: none;">. If you are writing code that needs to be very efficient</ins>, <ins style="font-weight: bold; text-decoration: none;">you</ins> <ins style="font-weight: bold; text-decoration: none;">can</ins> <ins style="font-weight: bold; text-decoration: none;">include assembly commands directly in your C code using <tt>asm</</ins>t<ins style="font-weight: bold; text-decoration: none;">>. As a simple example, the line <tt>asm("nop");</tt> will directly insert a nop in your compiled code. We will not</ins> go into assembly in more detail.</div></td>
</tr>
</table>Lynch