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authorFrederick Yin <fkfd@fkfd.me>2022-08-16 11:54:23 +0800
committerFrederick Yin <fkfd@fkfd.me>2022-08-16 11:54:23 +0800
commit9542deeb483a00b6fabed7574720926ce97d7511 (patch)
tree0f2c1f72c03dd4693fd59df67544d2a4dddc5494 /projects/08/FunctionCalls/NestedCall
parent9c0cb1d1c32724fc95ac9548e4f8d873d3adaccc (diff)
Projects, 01-06 completed
Diffstat (limited to 'projects/08/FunctionCalls/NestedCall')
-rw-r--r--projects/08/FunctionCalls/NestedCall/NestedCall.cmp2
-rw-r--r--projects/08/FunctionCalls/NestedCall/NestedCall.html196
-rw-r--r--projects/08/FunctionCalls/NestedCall/NestedCall.tst65
-rw-r--r--projects/08/FunctionCalls/NestedCall/NestedCallStack.html306
-rw-r--r--projects/08/FunctionCalls/NestedCall/NestedCallVME.tst70
-rw-r--r--projects/08/FunctionCalls/NestedCall/Sys.vm63
6 files changed, 702 insertions, 0 deletions
diff --git a/projects/08/FunctionCalls/NestedCall/NestedCall.cmp b/projects/08/FunctionCalls/NestedCall/NestedCall.cmp
new file mode 100644
index 0000000..9200202
--- /dev/null
+++ b/projects/08/FunctionCalls/NestedCall/NestedCall.cmp
@@ -0,0 +1,2 @@
+| RAM[0] | RAM[1] | RAM[2] | RAM[3] | RAM[4] | RAM[5] | RAM[6] |
+| 261 | 261 | 256 | 4000 | 5000 | 135 | 246 |
diff --git a/projects/08/FunctionCalls/NestedCall/NestedCall.html b/projects/08/FunctionCalls/NestedCall/NestedCall.html
new file mode 100644
index 0000000..0d8534d
--- /dev/null
+++ b/projects/08/FunctionCalls/NestedCall/NestedCall.html
@@ -0,0 +1,196 @@
+<!DOCTYPE html>
+<html>
+<head>
+ <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
+ <title>NestedCall.tst &mdash; Nand2Tetris Calling Convention Test</title>
+ <style type="text/css">
+ .code {font-family:"Courier New", Courier, monospace; font-size:90%;}
+ pre {margin-left:2em;}
+ </style>
+</head>
+<body>
+<!-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -->
+<h3>Synopsis</h3>
+<b>NestedCall.tst</b> is an intermediate test (in terms of complexity) intended to be used between the SimpleFunction and
+FibonacciElement tests. It may be useful when SimpleFunction passes but FibonacciElement fails or crashes. NestedCall also
+tests several requirements of the Function Calling Protocol that are not verified by the other
+supplied tests. NestedCall can be used with or without the VM bootstrap code.
+<p>
+<b>NestedCallVME.tst</b> runs the same test on the VM Emulator.
+<p>
+<b>The NestedCall</b> tests and supporting documentation were written by Mark Armbrust.
+
+<!-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -->
+<h3>Test Structure</h3>
+<h4>Startup</h4>
+NestedCall is implemented entirely within the Sys.vm file. The first function in Sys.vm is
+Sys.init(). This allows it to be used before the bootstrap code has been added to the VM Translator
+since there will be no file processing order issues.
+<p>
+NestedCall loads NestedCall.asm, sets up the stack to simulate the bootstrap's call to Sys.init(), then
+begins execution at the beginning of NestedCall.asm. If the bootstrap is not present, the program begins
+running with Sys.init() since it is the first function in Sys.vm.
+<p>
+If NestedCall.asm includes the bootstrap, the bootstrap will (re)initialize the stack and call Sys.init(),
+so the test should see the same environment either way it gets to Sys.init().
+<p>
+The test setup also initializes the LCL, ARG, THIS and THAT pointers to -1, -2, -3 and -4.
+
+<h4>Sys.init()</h4>
+
+<span class="code">THIS</span> and <span class="code">THAT</span> are set to known values so that context save and restore can be tested.
+<p>
+Sys.init() calls Sys.main() and stores the return value in <span class="code">temp 1</span>. This tests call to and
+return from a function with no arguments.
+
+<h4>Sys.main()</h4>
+Sys.main() allocates 5 local variables. It sets <span class="code">local 1</span>, <span class="code">local 2</span> and
+<span class="code">local 3</span>. <span class="code">local 0</span> and <span class="code">local 4</span> are intentionally not set.
+<p>
+<span class="code">THIS</span> and <span class="code">THAT</span> are changed so that context save and restore can be tested.
+<p>
+Sys.main() calls Sys.add12(123) and stores the return value in <span class="code">temp 0</span>. This tests call to and
+return from a function with arguments.
+<p>
+After Sys.add12() returns, Sys.main() sums <span class="code">local 0</span> through <span class="code">local 4</span> and returns the
+result. This tests that the local segment was properly allocated on the stack and that the local
+variables were not overwritten by the call to Sys.main(). It also tests that <span class="code">local 0</span> and
+<span class="code">local 4</span> were properly initialized to 0.
+
+<h4>Sys.add12()</h4>
+
+<span class="code">THIS</span> and <span class="code">THAT</span> are set to known values so that context save and restore can be tested.
+<p>
+Returns <span class="code">argument 0</span> plus 12.
+
+<!-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -->
+<h3>Test Coverage</h3>
+
+<p style="margin-left:1em; text-indent:-1em;">
+Functions with no arguments return to correct RIP (Return Instruction Point) with correct return value on stack.<br>
+This can fail if the RIP is not correctly pushed on the stack by the calling code, or if the returning
+code does not store the RIP in a temporary register before overwriting it with the return value.
+
+<p style="margin-left:1em; text-indent:-1em;">
+Functions with arguments return to correct RIP with correct return value on stack.<br>
+This can fail if it is assumed that <span class="code">ARG</span> points to the RIP.
+
+<p style="margin-left:1em; text-indent:-1em;">
+Functions with local variables allocate space on the stack for the local variables.<br>
+This can fail if the function prologue is not written or if the SP is not updated after zeroing
+the local variables.
+
+<p style="margin-left:1em; text-indent:-1em;">
+All local variables are initialized to 0.<br>
+Common errors are to forget this completely, or for the zeroing loop to be off by one.
+
+<p style="margin-left:1em; text-indent:-1em;">
+<span class="code">THIS</span> and <span class="code">THAT</span> are correctly retained across function calls. Looking ahead, in Project 9 you will be asked to write a simple computer game in the high-level Jack language. You can run your game (following compilation) on the supplied VM Emulator. But, if you choose to translate the VM code that the compiler generates using <em>your</em> VM Translator, then code like
+"<span class="code">push THIS</span>, <span class="code">push THAT</span> ... <span class="code">pop THIS</span>, <span class="code">pop THAT</span>" can cause some interesting failures!
+
+<!-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -->
+<h3>Debugging</h3>
+These comments assume that your VM translator has passed the SimpleFunction test.
+<p>
+If <span class="code">RAM[0]</span> is incorrect, you have a stack skew. More data was pushed onto the stack by
+<span class="code">call</span> than was popped by <span class="code">return</span>, or vice versa. See <i>debugging with
+breakpoints</i> later in this section.
+<p>
+If one or more of <span class="code">RAM[1]</span> through <span class="code">RAM[4]</span> is incorrect, the <span class="code">LCL</span>,
+<span class="code">ARG</span>, <span class="code">THIS</span> and <span class="code">THAT</span> pointers are not being correctly saved or restored.
+Most likely problem is when they are being saved; the SimpleFunction test verified that
+<span class="code">return</span> restored them correctly.
+<p>
+If <span class="code">RAM[5]</span> is incorrect there may be a problem with setting up the <span class="code">ARG</span> pointer.
+<p>
+If <span class="code">RAM[4]</span> is incorrect and <span class="code">RAM[5]</span> is correct, there may be a problem with
+allocation or initialization of local variables.
+
+<h4>Debugging with breakpoints</h4>
+
+To find tough bugs you can use the "breakpoint" facility in the CPU Emulator (red flag button).
+You can use breakpoints to have you program stop when it gets to a particular RAM address. For
+example:<br>
+&emsp;&bull;&ensp;load the NestedCall.tst file,<br>
+&emsp;&bull;&ensp;set a PC breakpoint at the ROM address for <span class="code">(Sys.main)</span>,<br>
+&emsp;&bull;&ensp;hit the run button.<br>
+When the CPU Emulator stops at the breakpoint you can inspect the RAM to check the stack and pointers values.
+(If the breakpoint isn't hit, you will need to to single-step debug through
+your calling code to see why it didn't get there.)
+<p>
+Other useful places to set breakpoints are the entry points to the other functions and at the
+first and final instructions generated for <span class="code">return</span> commands.
+<p>
+<a href="NestedCallStack.html">NestedCallStack.html</a> shows the expected stack values at various points
+during the test.
+
+<h4>Finding ROM address in your ASM code</h4>
+It is not easy to find the ROM locations where you want to set breakpoints, because there is no
+one-to-one correspondence between the ASM file line numbers and the ROM addresses. This is made even more
+difficult because the supplied CPU Emulator does not display the (LABELS) in its ROM panel.
+<p>
+There are two things that you can do to make this easier.
+<p>
+<h5>Modify your assembler to generate a listing file.</h5>
+A listing file shows all the ASM source lines, including comments, as well as the ROM addresses and
+the values of the labels and the instructions. For example, here is a snippet of a listing file generated by an assembler written by Mark Armbrust:
+<pre>
+ 20 16 @i // i -= 1
+ 21 FC88 M=M-1
+
+ 22 FC10 D=M // if i > 0
+ 23 6 @LOOP
+ 24 E301 D;JGT // goto LOOP
+
+ 25 (STOP)
+ 25 25 @STOP
+ 26 EA87 0;JMP
+
+Data Symbols
+
+ 16 D i
+
+Code Symbols
+
+ 6 C LOOP
+ 17 C SKIP
+ 25 C STOP
+</pre>
+For the Nand2Tetris environment, it is most useful to list the ROM addresses and A-instruction
+values in decimal. In the above snippet, the C-instruction values are
+listed in hexadecimal.
+<p>
+The list file is generated during pass 2 of the Assembler, parallel to generating the .hack file. To
+make it easier to handle blank and comment only lines, Mark has Parser.commandType() return
+NO_COMMAND for source lines with no command. Mark also added Parser.sourceLine() that returns the
+unmodified source line.
+<p>
+<h5>Have your VM Translator write the VM source lines as comments in the ASM output.</h5>
+For example:
+<pre>
+ // label LOOP
+(Sys.init$LOOP)
+ // goto LOOP
+@Sys.init$LOOP
+0;JMP
+ //
+ // // Sys.main()
+ //
+ // // Sets locals 1, 2 and 3, leaving locals 0 and 4 unchanged to test
+ // // default local initialization to 0. (RAM set to -1 by test setup.)
+ // // Calls Sys.add12(123) and stores return value (135) in temp 0.
+ // // Returns local 0 + local 1 + local 2 + local 3 + local 4 (456) to confirm
+ // // that locals were not mangled by function call.
+ //
+ // function Sys.main 5
+(Sys.main)
+@5
+D=-A
+($3)
+@SP
+</pre>
+Note that comments in the VM source become double comments. Looking ahead, in Project 11 you will be asked to write a compiler for the Jack language. If your compiler will write the Jack source lines as comments in the
+generated VM files, this convention will be quite useful.
+
+</body>
+</html> \ No newline at end of file
diff --git a/projects/08/FunctionCalls/NestedCall/NestedCall.tst b/projects/08/FunctionCalls/NestedCall/NestedCall.tst
new file mode 100644
index 0000000..70e5523
--- /dev/null
+++ b/projects/08/FunctionCalls/NestedCall/NestedCall.tst
@@ -0,0 +1,65 @@
+// Test file for NestedCall test.
+
+load NestedCall.asm,
+output-file NestedCall.out,
+compare-to NestedCall.cmp,
+output-list RAM[0]%D1.6.1 RAM[1]%D1.6.1 RAM[2]%D1.6.1 RAM[3]%D1.6.1 RAM[4]%D1.6.1 RAM[5]%D1.6.1 RAM[6]%D1.6.1;
+
+set RAM[0] 261,
+set RAM[1] 261,
+set RAM[2] 256,
+set RAM[3] -3,
+set RAM[4] -4,
+set RAM[5] -1, // test results
+set RAM[6] -1,
+set RAM[256] 1234, // fake stack frame from call Sys.init
+set RAM[257] -1,
+set RAM[258] -2,
+set RAM[259] -3,
+set RAM[260] -4,
+
+set RAM[261] -1, // Initialize stack to check for local segment
+set RAM[262] -1, // being cleared to zero.
+set RAM[263] -1,
+set RAM[264] -1,
+set RAM[265] -1,
+set RAM[266] -1,
+set RAM[267] -1,
+set RAM[268] -1,
+set RAM[269] -1,
+set RAM[270] -1,
+set RAM[271] -1,
+set RAM[272] -1,
+set RAM[273] -1,
+set RAM[274] -1,
+set RAM[275] -1,
+set RAM[276] -1,
+set RAM[277] -1,
+set RAM[278] -1,
+set RAM[279] -1,
+set RAM[280] -1,
+set RAM[281] -1,
+set RAM[282] -1,
+set RAM[283] -1,
+set RAM[284] -1,
+set RAM[285] -1,
+set RAM[286] -1,
+set RAM[287] -1,
+set RAM[288] -1,
+set RAM[289] -1,
+set RAM[290] -1,
+set RAM[291] -1,
+set RAM[292] -1,
+set RAM[293] -1,
+set RAM[294] -1,
+set RAM[295] -1,
+set RAM[296] -1,
+set RAM[297] -1,
+set RAM[298] -1,
+set RAM[299] -1,
+
+repeat 4000 {
+ ticktock;
+}
+
+output;
diff --git a/projects/08/FunctionCalls/NestedCall/NestedCallStack.html b/projects/08/FunctionCalls/NestedCall/NestedCallStack.html
new file mode 100644
index 0000000..70582b6
--- /dev/null
+++ b/projects/08/FunctionCalls/NestedCall/NestedCallStack.html
@@ -0,0 +1,306 @@
+<!DOCTYPE html>
+<html>
+<head>
+ <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
+ <title>NestedCall.tst &mdash; Stack Frames</title>
+ <style type="text/css">
+ .stack {border-collapse:collapse; font-size:80%;}
+ .stack td {padding-left:.25em;padding-right:.25em;white-space:nowrap;}
+ .stack td:first-child {text-align:right;}
+ .stack td:first-child + td {text-align:right;}
+ .stack td:first-child + td + td {text-align:left;}
+ .stack td:first-child + td + td + td {text-align:left;}
+ .stack .reg {border-left:1px solid; border-right:1px solid;}
+ .stack .reg th {border:1px solid;}
+ .stack .stack {border-left:1px solid; border-right:1px solid;}
+ .stack .stack th {border:1px solid;}
+ .stack .tos {border-left:1px solid; border-right:1px solid;border-bottom:1px solid;}
+ .stack .frame {border-left:1px solid; border-right:1px solid;}
+ .stack .frame td:first-child + td {border-left:1px solid;}
+ .stack .frame td:first-child + td + td {border-right:1px solid;}
+ .stack .framet {border-left:1px solid; border-right:1px solid;}
+ .stack .framet td:first-child + td {border-left:1px solid;border-top:1px solid;}
+ .stack .framet td:first-child + td + td {border-right:1px solid;border-top:1px solid;}
+ .stack .bframe {border-left:1px solid; border-right:1px solid;}
+ .stack .bframe td:first-child + td {border-left:2px solid;}
+ .stack .bframe td:first-child + td + td {border-right:2px solid;}
+ .stack .bframet {border-left:1px solid; border-right:1px solid;}
+ .stack .bframet td:first-child + td {border-left:2px solid;border-top:2px solid;}
+ .stack .bframet td:first-child + td + td {border-right:2px solid;border-top:2px solid;}
+ .stack .bframeb {border-left:1px solid; border-right:1px solid;}
+ .stack .bframeb td:first-child + td {border-left:2px solid;border-bottom:2px solid;}
+ .stack .bframeb td:first-child + td + td {border-right:2px solid;border-bottom:2px solid;}
+ .stack .note td {padding-left:.5em;padding-right:.5em;white-space:normal;text-align:justify;}
+ .stack .fid {font-style:italic}
+ .master {width: 10%;}
+ .master td {vertical-align:top;padding-right:.5em; }
+ </style>
+</head>
+<body>
+<!-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -->
+<table class="master">
+<tr>
+ <td>
+ <table class="stack">
+ <tr><th colspan="4">Bootstrap init</th></tr>
+ <tr class="reg"><th colspan="4">Pointers</th></tr>
+ <tr class="reg"><td>0</td><td>256</td><td>SP</td><td></td></tr>
+ <tr class="reg"><td>1</td><td>-1</td><td>LCL</td><td></td></tr>
+ <tr class="reg"><td>2</td><td>-2</td><td>ARG</td><td></td></tr>
+ <tr class="reg"><td>3</td><td>-3</td><td>THIS</td><td></td></tr>
+ <tr class="reg"><td>4</td><td>-4</td><td>THAT</td><td></td></tr>
+ <tr class="stack"><th colspan="4">Stack</th></tr>
+ <tr class="tos"><td>256</td><td>???</td><td></td><td>&larr;SP</td></tr>
+ <tr class="note"><td colspan="4"><br>
+ This is how my boot&shy;strap code initial&shy;izes the pointers before calling Sys.init().
+ <p>
+ Setting the LCL, ARG, THIS and THAT point&shy;ers to known illegal values helps identify
+ when a pointer is used before it is initial&shy;ized.
+ <p>
+ (If you are running the NestedCall test with&shy;out boot&shy;strap code, you will not see this state.)</td></tr>
+ </table>
+ </td><td>
+ <table class="stack">
+ <tr><th colspan="4">Entry to Sys.init()</th></tr>
+ <tr class="reg"><th colspan="4">Pointers</th></tr>
+ <tr class="reg"><td>0</td><td>261</td><td>SP</td><td></td></tr>
+ <tr class="reg"><td>1</td><td>261</td><td>LCL</td><td></td></tr>
+ <tr class="reg"><td>2</td><td>256</td><td>ARG</td><td></td></tr>
+ <tr class="reg"><td>3</td><td>-3</td><td>THIS</td><td></td></tr>
+ <tr class="reg"><td>4</td><td>-4</td><td>THAT</td><td></td></tr>
+ <tr class="stack"><th colspan="4">Stack</th></tr>
+ <tr class="bframet"><td>256</td><td>*</td><td>Return IP</td><td>&larr;ARG</td></tr>
+ <tr class="bframe"><td>257</td><td>-1</td><td>Saved LCL</td><td></td></tr>
+ <tr class="bframe"><td>258</td><td>-2</td><td>Saved ARG</td><td class="fid">Sys.init</td></tr>
+ <tr class="bframe"><td>259</td><td>-3</td><td>Saved THIS</td><td class="fid">&ensp;frame</td></tr>
+ <tr class="bframeb"><td>260</td><td>-4</td><td>Saved THAT</td><td></td></tr>
+ <tr class="tos"><td>261</td><td>???</td><td></td><td>&larr;LCL, SP</td></tr>
+ <tr class="note"><td colspan="4"><br>
+ This is how NestedCall.tst initial&shy;izes the pointers and stack. This is what RAM looks
+ like after my boot&shy;strap calls Sys.init().
+ <p>
+ (If your VM trans&shy;lation includes the boot&shy;strap, the -1 through -4 values may be
+ different if your boot&shy;strap initial&shy;izes them.)</td></tr>
+ </table>
+ </td><td>
+ <table class="stack">
+ <tr><th colspan="4">Entry to Sys.main()</th></tr>
+ <tr class="reg"><th colspan="4">Pointers</th></tr>
+ <tr class="reg"><td>0</td><td>266</td><td>SP</td><td></td></tr>
+ <tr class="reg"><td>1</td><td>266</td><td>LCL</td><td></td></tr>
+ <tr class="reg"><td>2</td><td>261</td><td>ARG</td><td></td></tr>
+ <tr class="reg"><td>3</td><td>4000</td><td>THIS</td><td></td></tr>
+ <tr class="reg"><td>4</td><td>5000</td><td>THAT</td><td></td></tr>
+ <tr class="stack"><th colspan="4">Stack</th></tr>
+ <tr class="framet"><td>256</td><td>*</td><td>Return IP</td><td></td></tr>
+ <tr class="frame"><td>257</td><td>-1</td><td>Saved LCL</td><td></td></tr>
+ <tr class="frame"><td>258</td><td>-2</td><td>Saved ARG</td><td class="fid">Sys.init</td></tr>
+ <tr class="frame"><td>259</td><td>-3</td><td>Saved THIS</td><td class="fid">&ensp;frame</td></tr>
+ <tr class="frame"><td>260</td><td>-4</td><td>Saved THAT</td><td></td></tr>
+ <tr class="bframet"><td>261</td><td>*</td><td>Return IP</td><td>&larr;ARG</td></tr>
+ <tr class="bframe"><td>262</td><td>261</td><td>Saved LCL</td><td></td></tr>
+ <tr class="bframe"><td>263</td><td>256</td><td>Saved ARG</td><td class="fid">Sys.main</td></tr>
+ <tr class="bframe"><td>264</td><td>4000</td><td>Saved THIS</td><td class="fid">&ensp;frame</td></tr>
+ <tr class="bframeb"><td>265</td><td>5000</td><td>Saved THAT</td><td></td></tr>
+ <tr class="tos"><td>266</td><td>???</td><td></td><td>&larr;LCL, SP</td></tr>
+ </table>
+ </td><td>
+ <table class="stack">
+ <tr><th colspan="4">After Sys.main() prologue</th></tr>
+ <tr class="reg"><th colspan="4">Pointers</th></tr>
+ <tr class="reg"><td>0</td><td>271</td><td>SP</td><td></td></tr>
+ <tr class="reg"><td>1</td><td>266</td><td>LCL</td><td></td></tr>
+ <tr class="reg"><td>2</td><td>261</td><td>ARG</td><td></td></tr>
+ <tr class="reg"><td>3</td><td>4000</td><td>THIS</td><td></td></tr>
+ <tr class="reg"><td>4</td><td>5000</td><td>THAT</td><td></td></tr>
+ <tr class="stack"><th colspan="4">Stack</th></tr>
+ <tr class="framet"><td>256</td><td>*</td><td>Return IP</td><td></td></tr>
+ <tr class="frame"><td>257</td><td>-1</td><td>Saved LCL</td><td></td></tr>
+ <tr class="frame"><td>258</td><td>-2</td><td>Saved ARG</td><td class="fid">Sys.init</td></tr>
+ <tr class="frame"><td>259</td><td>-3</td><td>Saved THIS</td><td class="fid">&ensp;frame</td></tr>
+ <tr class="frame"><td>260</td><td>-4</td><td>Saved THAT</td><td></td></tr>
+ <tr class="bframet"><td>261</td><td>*</td><td>Return IP</td><td>&larr;ARG</td></tr>
+ <tr class="bframe"><td>262</td><td>261</td><td>Saved LCL</td><td></td></tr>
+ <tr class="bframe"><td>263</td><td>256</td><td>Saved ARG</td><td class="fid">Sys.main</td></tr>
+ <tr class="bframe"><td>264</td><td>4000</td><td>Saved THIS</td><td class="fid">&ensp;frame</td></tr>
+ <tr class="bframe"><td>265</td><td>5000</td><td>Saved THAT</td><td></td></tr>
+ <tr class="bframe"><td>266</td><td>0</td><td>local 0</td><td>&larr;LCL</td></tr>
+ <tr class="bframe"><td>267</td><td>0</td><td>local 1</td><td></td></tr>
+ <tr class="bframe"><td>268</td><td>0</td><td>local 2</td><td></td></tr>
+ <tr class="bframe"><td>269</td><td>0</td><td>local 3</td><td></td></tr>
+ <tr class="bframeb"><td>270</td><td>0</td><td>local 4</td><td></td></tr>
+ <tr class="tos"><td>271</td><td>???</td><td></td><td>&larr;SP</td></tr>
+ <tr class="note"><td colspan="4"><br>
+ The <i>function prologue</i> is the assembly language code generated for the
+ "function" VM command.
+ </table>
+ </td><td>
+ <table class="stack">
+ <tr><th colspan="4">Entry to Sys.add12(123)</th></tr>
+ <tr class="reg"><th colspan="4">Pointers</th></tr>
+ <tr class="reg"><td>0</td><td>277</td><td>SP</td><td></td></tr>
+ <tr class="reg"><td>1</td><td>277</td><td>LCL</td><td></td></tr>
+ <tr class="reg"><td>2</td><td>271</td><td>ARG</td><td></td></tr>
+ <tr class="reg"><td>3</td><td>4001</td><td>THIS</td><td></td></tr>
+ <tr class="reg"><td>4</td><td>5001</td><td>THAT</td><td></td></tr>
+ <tr class="stack"><th colspan="4">Stack</th></tr>
+ <tr class="framet"><td>256</td><td>*</td><td>Return IP</td><td></td></tr>
+ <tr class="frame"><td>257</td><td>-1</td><td>Saved LCL</td><td></td></tr>
+ <tr class="frame"><td>258</td><td>-2</td><td>Saved ARG</td><td class="fid">Sys.init</td></tr>
+ <tr class="frame"><td>259</td><td>-3</td><td>Saved THIS</td><td class="fid">&ensp;frame</td></tr>
+ <tr class="frame"><td>260</td><td>-4</td><td>Saved THAT</td><td></td></tr>
+ <tr class="framet"><td>261</td><td>*</td><td>Return IP</td><td></td></tr>
+ <tr class="frame"><td>262</td><td>261</td><td>Saved LCL</td><td></td></tr>
+ <tr class="frame"><td>263</td><td>256</td><td>Saved ARG</td><td class="fid">Sys.main</td></tr>
+ <tr class="frame"><td>264</td><td>4000</td><td>Saved THIS</td><td class="fid">&ensp;frame</td></tr>
+ <tr class="frame"><td>265</td><td>5000</td><td>Saved THAT</td><td></td></tr>
+ <tr class="frame"><td>266</td><td>0</td><td>local 0</td><td></td></tr>
+ <tr class="frame"><td>267</td><td>200</td><td>local 1</td><td></td></tr>
+ <tr class="frame"><td>268</td><td>40</td><td>local 2</td><td></td></tr>
+ <tr class="frame"><td>269</td><td>6</td><td>local 3</td><td></td></tr>
+ <tr class="frame"><td>270</td><td>0</td><td>local 4</td><td></td></tr>
+ <tr class="bframet"><td>271</td><td>123</td><td>argument 0</td><td>&larr;ARG</td></tr>
+ <tr class="bframe"><td>272</td><td>*</td><td>Return IP</td><td></td></tr>
+ <tr class="bframe"><td>273</td><td>266</td><td>Saved LCL</td><td class="fid">Sys.add12</td></tr>
+ <tr class="bframe"><td>274</td><td>261</td><td>Saved ARG</td><td class="fid">&ensp;frame</td></tr>
+ <tr class="bframe"><td>275</td><td>4001</td><td>Saved THIS</td><td></td></tr>
+ <tr class="bframeb"><td>276</td><td>5001</td><td>Saved THAT</td><td></td></tr>
+ <tr class="tos"><td>277</td><td>???</td><td></td><td>&larr;LCL, SP</td></tr>
+ </table>
+ </td>
+</tr></table>
+
+<p>
+
+<table class="master">
+<tr>
+ <td>
+ <table class="stack">
+ <tr><th colspan="4">Before Sys.add12() return</th></tr>
+ <tr class="reg"><th colspan="4">Pointers</th></tr>
+ <tr class="reg"><td>0</td><td>278</td><td>SP</td><td></td></tr>
+ <tr class="reg"><td>1</td><td>277</td><td>LCL</td><td></td></tr>
+ <tr class="reg"><td>2</td><td>271</td><td>ARG</td><td></td></tr>
+ <tr class="reg"><td>3</td><td>4002</td><td>THIS</td><td></td></tr>
+ <tr class="reg"><td>4</td><td>5002</td><td>THAT</td><td></td></tr>
+ <tr class="stack"><th colspan="4">Stack</th></tr>
+ <tr class="framet"><td>256</td><td>*</td><td>Return IP</td><td></td></tr>
+ <tr class="frame"><td>257</td><td>-1</td><td>Saved LCL</td><td></td></tr>
+ <tr class="frame"><td>258</td><td>-2</td><td>Saved ARG</td><td class="fid">Sys.init</td></tr>
+ <tr class="frame"><td>259</td><td>-3</td><td>Saved THIS</td><td class="fid">&ensp;frame</td></tr>
+ <tr class="frame"><td>260</td><td>-4</td><td>Saved THAT</td><td></td></tr>
+ <tr class="framet"><td>261</td><td>*</td><td>Return IP</td><td></td></tr>
+ <tr class="frame"><td>262</td><td>261</td><td>Saved LCL</td><td></td></tr>
+ <tr class="frame"><td>263</td><td>256</td><td>Saved ARG</td><td class="fid">Sys.main</td></tr>
+ <tr class="frame"><td>264</td><td>4000</td><td>Saved THIS</td><td class="fid">&ensp;frame</td></tr>
+ <tr class="frame"><td>265</td><td>5000</td><td>Saved THAT</td><td></td></tr>
+ <tr class="frame"><td>266</td><td>0</td><td>local 0</td><td></td></tr>
+ <tr class="frame"><td>267</td><td>200</td><td>local 1</td><td></td></tr>
+ <tr class="frame"><td>268</td><td>40</td><td>local 2</td><td></td></tr>
+ <tr class="frame"><td>269</td><td>6</td><td>local 3</td><td></td></tr>
+ <tr class="frame"><td>270</td><td>0</td><td>local 4</td><td></td></tr>
+ <tr class="bframet"><td>271</td><td>123</td><td>argument 0</td><td>&larr;ARG</td></tr>
+ <tr class="bframe"><td>272</td><td>*</td><td>Return IP</td><td></td></tr>
+ <tr class="bframe"><td>273</td><td>266</td><td>Saved LCL</td><td class="fid">Sys.add12</td></tr>
+ <tr class="bframe"><td>274</td><td>261</td><td>Saved ARG</td><td class="fid">&ensp;frame</td></tr>
+ <tr class="bframe"><td>275</td><td>4001</td><td>Saved THIS</td><td></td></tr>
+ <tr class="bframe"><td>276</td><td>5001</td><td>Saved THAT</td><td></td></tr>
+ <tr class="bframeb"><td>277</td><td>135</td><td>Return value</td><td>&larr;LCL</td></tr>
+ <tr class="tos"><td>278</td><td>???</td><td></td><td>&larr;SP</td></tr>
+ </table>
+ </td><td>
+ <table class="stack">
+ <tr><th colspan="4">After Sys.add12() return</th></tr>
+ <tr class="reg"><th colspan="4">Pointers</th></tr>
+ <tr class="reg"><td>0</td><td>272</td><td>SP</td><td></td></tr>
+ <tr class="reg"><td>1</td><td>266</td><td>LCL</td><td></td></tr>
+ <tr class="reg"><td>2</td><td>261</td><td>ARG</td><td></td></tr>
+ <tr class="reg"><td>3</td><td>4001</td><td>THIS</td><td></td></tr>
+ <tr class="reg"><td>4</td><td>5001</td><td>THAT</td><td></td></tr>
+ <tr class="stack"><th colspan="4">Stack</th></tr>
+ <tr class="framet"><td>256</td><td>*</td><td>Return IP</td><td></td></tr>
+ <tr class="frame"><td>257</td><td>-1</td><td>Saved LCL</td><td></td></tr>
+ <tr class="frame"><td>258</td><td>-2</td><td>Saved ARG</td><td class="fid">Sys.init</td></tr>
+ <tr class="frame"><td>259</td><td>-3</td><td>Saved THIS</td><td class="fid">&ensp;frame</td></tr>
+ <tr class="frame"><td>260</td><td>-4</td><td>Saved THAT</td><td></td></tr>
+ <tr class="bframet"><td>261</td><td>*</td><td>Return IP</td><td>&larr;ARG</td></tr>
+ <tr class="bframe"><td>262</td><td>261</td><td>Saved LCL</td><td></td></tr>
+ <tr class="bframe"><td>263</td><td>256</td><td>Saved ARG</td><td class="fid">Sys.main</td></tr>
+ <tr class="bframe"><td>264</td><td>4000</td><td>Saved THIS</td><td class="fid">&ensp;frame</td></tr>
+ <tr class="bframe"><td>265</td><td>5000</td><td>Saved THAT</td><td></td></tr>
+ <tr class="bframe"><td>266</td><td>0</td><td>local 0</td><td>&larr;LCL</td></tr>
+ <tr class="bframe"><td>267</td><td>200</td><td>local 1</td><td></td></tr>
+ <tr class="bframe"><td>268</td><td>40</td><td>local 2</td><td></td></tr>
+ <tr class="bframe"><td>269</td><td>6</td><td>local 3</td><td></td></tr>
+ <tr class="bframe"><td>270</td><td>0</td><td>local 4</td><td></td></tr>
+ <tr class="bframeb"><td>271</td><td>135</td><td>Return value</td><td></td></tr>
+ <tr class="tos"><td>272</td><td>???</td><td></td><td>&larr;SP</td></tr>
+ </table>
+ </td><td>
+ <table class="stack">
+ <tr><th colspan="4">Before Sys.main() return</th></tr>
+ <tr class="reg"><th colspan="4">Pointers</th></tr>
+ <tr class="reg"><td>0</td><td>272</td><td>SP</td><td></td></tr>
+ <tr class="reg"><td>1</td><td>266</td><td>LCL</td><td></td></tr>
+ <tr class="reg"><td>2</td><td>261</td><td>ARG</td><td></td></tr>
+ <tr class="reg"><td>3</td><td>4001</td><td>THIS</td><td></td></tr>
+ <tr class="reg"><td>4</td><td>5001</td><td>THAT</td><td></td></tr>
+ <tr class="stack"><th colspan="4">Stack</th></tr>
+ <tr class="framet"><td>256</td><td>*</td><td>Return IP</td><td></td></tr>
+ <tr class="frame"><td>257</td><td>-1</td><td>Saved LCL</td><td></td></tr>
+ <tr class="frame"><td>258</td><td>-2</td><td>Saved ARG</td><td class="fid">Sys.init</td></tr>
+ <tr class="frame"><td>259</td><td>-3</td><td>Saved THIS</td><td class="fid">&ensp;frame</td></tr>
+ <tr class="frame"><td>260</td><td>-4</td><td>Saved THAT</td><td></td></tr>
+ <tr class="bframet"><td>261</td><td>*</td><td>Return IP</td><td>&larr;ARG</td></tr>
+ <tr class="bframe"><td>262</td><td>261</td><td>Saved LCL</td><td></td></tr>
+ <tr class="bframe"><td>263</td><td>256</td><td>Saved ARG</td><td class="fid">Sys.main</td></tr>
+ <tr class="bframe"><td>264</td><td>4000</td><td>Saved THIS</td><td class="fid">&ensp;frame</td></tr>
+ <tr class="bframe"><td>265</td><td>5000</td><td>Saved THAT</td><td></td></tr>
+ <tr class="bframe"><td>266</td><td>0</td><td>local 0</td><td>&larr;LCL</td></tr>
+ <tr class="bframe"><td>267</td><td>200</td><td>local 1</td><td></td></tr>
+ <tr class="bframe"><td>268</td><td>40</td><td>local 2</td><td></td></tr>
+ <tr class="bframe"><td>269</td><td>6</td><td>local 3</td><td></td></tr>
+ <tr class="bframe"><td>270</td><td>0</td><td>local 4</td><td></td></tr>
+ <tr class="bframeb"><td>271</td><td>246</td><td>Return value</td><td></td></tr>
+ <tr class="tos"><td>272</td><td>???</td><td></td><td>&larr;SP</td></tr>
+ </table>
+ </td><td>
+ <table class="stack">
+ <tr><th colspan="4">After Sys.main() return</th></tr>
+ <tr class="reg"><th colspan="4">Pointers</th></tr>
+ <tr class="reg"><td>0</td><td>262</td><td>SP</td><td></td></tr>
+ <tr class="reg"><td>1</td><td>261</td><td>LCL</td><td></td></tr>
+ <tr class="reg"><td>2</td><td>256</td><td>ARG</td><td></td></tr>
+ <tr class="reg"><td>3</td><td>4000</td><td>THIS</td><td></td></tr>
+ <tr class="reg"><td>4</td><td>5000</td><td>THAT</td><td></td></tr>
+ <tr class="stack"><th colspan="4">Stack</th></tr>
+ <tr class="bframet"><td>256</td><td>*</td><td>Return IP</td><td>&larr;ARG</td></tr>
+ <tr class="bframe"><td>257</td><td>-1</td><td>Saved LCL</td><td></td></tr>
+ <tr class="bframe"><td>258</td><td>-2</td><td>Saved ARG</td><td class="fid">Sys.init</td></tr>
+ <tr class="bframe"><td>259</td><td>-3</td><td>Saved THIS</td><td class="fid">&ensp;frame</td></tr>
+ <tr class="bframe"><td>260</td><td>-4</td><td>Saved THAT</td><td></td></tr>
+ <tr class="bframeb"><td>261</td><td>246</td><td>Return value</td><td>&larr;LCL</td></tr>
+ <tr class="tos"><td>262</td><td>???</td><td></td><td>&larr;SP</td></tr>
+ </table>
+ </td><td>
+ <table class="stack">
+ <tr><th colspan="4">In Sys.init() halt loop</th></tr>
+ <tr class="reg"><th colspan="4">Pointers</th></tr>
+ <tr class="reg"><td>0</td><td>261</td><td>SP</td><td></td></tr>
+ <tr class="reg"><td>1</td><td>261</td><td>LCL</td><td></td></tr>
+ <tr class="reg"><td>2</td><td>256</td><td>ARG</td><td></td></tr>
+ <tr class="reg"><td>3</td><td>4000</td><td>THIS</td><td></td></tr>
+ <tr class="reg"><td>4</td><td>5000</td><td>THAT</td><td></td></tr>
+ <tr class="stack"><th colspan="4">Stack</th></tr>
+ <tr class="bframet"><td>256</td><td>*</td><td>Return IP</td><td>&larr;ARG</td></tr>
+ <tr class="bframe"><td>257</td><td>-1</td><td>Saved LCL</td><td></td></tr>
+ <tr class="bframe"><td>258</td><td>-2</td><td>Saved ARG</td><td class="fid">Sys.init</td></tr>
+ <tr class="bframe"><td>259</td><td>-3</td><td>Saved THIS</td><td class="fid">&ensp;frame</td></tr>
+ <tr class="bframeb"><td>260</td><td>-4</td><td>Saved THAT</td><td></td></tr>
+ <tr class="tos"><td>261</td><td>???</td><td></td><td>&larr;LCL, SP</td></tr>
+ </table>
+ </td>
+</tr></table>
+
+</body>
+</html> \ No newline at end of file
diff --git a/projects/08/FunctionCalls/NestedCall/NestedCallVME.tst b/projects/08/FunctionCalls/NestedCall/NestedCallVME.tst
new file mode 100644
index 0000000..2c689b8
--- /dev/null
+++ b/projects/08/FunctionCalls/NestedCall/NestedCallVME.tst
@@ -0,0 +1,70 @@
+// Test file for NestedCall test.
+
+load Sys.vm,
+output-file NestedCall.out,
+compare-to NestedCall.cmp,
+output-list RAM[0]%D1.6.1 RAM[1]%D1.6.1 RAM[2]%D1.6.1 RAM[3]%D1.6.1 RAM[4]%D1.6.1 RAM[5]%D1.6.1 RAM[6]%D1.6.1;
+
+set RAM[0] 261,
+set RAM[1] 261,
+set RAM[2] 256,
+set RAM[3] -3,
+set RAM[4] -4,
+set RAM[5] -1, // test results
+set RAM[6] -1,
+set RAM[256] 1234, // fake stack frame from call Sys.init
+set RAM[257] -1,
+set RAM[258] -2,
+set RAM[259] -3,
+set RAM[260] -4,
+
+set RAM[261] -1, // Initialize stack to check for local segment
+set RAM[262] -1, // being cleared to zero.
+set RAM[263] -1,
+set RAM[264] -1,
+set RAM[265] -1,
+set RAM[266] -1,
+set RAM[267] -1,
+set RAM[268] -1,
+set RAM[269] -1,
+set RAM[270] -1,
+set RAM[271] -1,
+set RAM[272] -1,
+set RAM[273] -1,
+set RAM[274] -1,
+set RAM[275] -1,
+set RAM[276] -1,
+set RAM[277] -1,
+set RAM[278] -1,
+set RAM[279] -1,
+set RAM[280] -1,
+set RAM[281] -1,
+set RAM[282] -1,
+set RAM[283] -1,
+set RAM[284] -1,
+set RAM[285] -1,
+set RAM[286] -1,
+set RAM[287] -1,
+set RAM[288] -1,
+set RAM[289] -1,
+set RAM[290] -1,
+set RAM[291] -1,
+set RAM[292] -1,
+set RAM[293] -1,
+set RAM[294] -1,
+set RAM[295] -1,
+set RAM[296] -1,
+set RAM[297] -1,
+set RAM[298] -1,
+set RAM[299] -1,
+
+set sp 261,
+set local 261,
+set argument 256,
+set this 3000,
+set that 4000;
+
+repeat 50 {
+ vmstep;
+}
+output;
diff --git a/projects/08/FunctionCalls/NestedCall/Sys.vm b/projects/08/FunctionCalls/NestedCall/Sys.vm
new file mode 100644
index 0000000..8b0b003
--- /dev/null
+++ b/projects/08/FunctionCalls/NestedCall/Sys.vm
@@ -0,0 +1,63 @@
+// Sys.vm for NestedCall test.
+
+// Sys.init()
+//
+// Calls Sys.main() and stores return value in temp 1.
+// Does not return. (Enters infinite loop.)
+
+function Sys.init 0
+push constant 4000 // test THIS and THAT context save
+pop pointer 0
+push constant 5000
+pop pointer 1
+call Sys.main 0
+pop temp 1
+label LOOP
+goto LOOP
+
+// Sys.main()
+//
+// Sets locals 1, 2 and 3, leaving locals 0 and 4 unchanged to test
+// default local initialization to 0. (RAM set to -1 by test setup.)
+// Calls Sys.add12(123) and stores return value (135) in temp 0.
+// Returns local 0 + local 1 + local 2 + local 3 + local 4 (456) to confirm
+// that locals were not mangled by function call.
+
+function Sys.main 5
+push constant 4001
+pop pointer 0
+push constant 5001
+pop pointer 1
+push constant 200
+pop local 1
+push constant 40
+pop local 2
+push constant 6
+pop local 3
+push constant 123
+call Sys.add12 1
+pop temp 0
+push local 0
+push local 1
+push local 2
+push local 3
+push local 4
+add
+add
+add
+add
+return
+
+// Sys.add12(int n)
+//
+// Returns n+12.
+
+function Sys.add12 0
+push constant 4002
+pop pointer 0
+push constant 5002
+pop pointer 1
+push argument 0
+push constant 12
+add
+return
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-22 14:43:23 +0000