[07/Pointers] Implemented pointer segment push/pop

master
Nemo 3 years ago
parent 16e830851e
commit 67b4e2653e
  1. 4
      README.md
  2. 127
      projects/07/MemoryAccess/PointerTest/PointerTest.asm
  3. 2
      projects/07/MemoryAccess/PointerTest/PointerTest.out
  4. 24
      vm/CodeWriter.php

@ -108,6 +108,6 @@ wc -l file.hack
### Memory Access Commands
- [x] BasicTest.vm
- [ ] PointerTest.vm
- [x] BasicTest.vm (228)
- [x] PointerTest.vm (127)
- [ ] StackTest.vm

@ -0,0 +1,127 @@
@3030 // push constant 3030
D=A
@SP
A=M
M=D
@SP
M=M+1 // end push constant 3030 (L0)
@SP // pop
AM=M-1
D=M
@THIS
M=D // (L1)
@3040 // push constant 3040
D=A
@SP
A=M
M=D
@SP
M=M+1 // end push constant 3040 (L2)
@SP // pop
AM=M-1
D=M
@THAT
M=D // (L3)
@32 // push constant 32
D=A
@SP
A=M
M=D
@SP
M=M+1 // end push constant 32 (L4)
@THIS // this 2
D=M
@2 // write 2 to A
D=D+A // D = segment+index
@R13 // save it to R13
M=D // write @THIS+2 to R13
@SP // pop
AM=M-1
D=M
@R13
A=M // Read @R13 to A (for this 2)
M=D // end pop this 2 (L5)
@46 // push constant 46
D=A
@SP
A=M
M=D
@SP
M=M+1 // end push constant 46 (L6)
@THAT // that 6
D=M
@6 // write 6 to A
D=D+A // D = segment+index
@R13 // save it to R13
M=D // write @THAT+6 to R13
@SP // pop
AM=M-1
D=M
@R13
A=M // Read @R13 to A (for that 6)
M=D // end pop that 6 (L7)
@THIS // pointer 0
D=M
@SP
A=M
M=D
@SP
M=M+1 // end push pointer 0 (L8)
@THAT // pointer 1
D=M
@SP
A=M
M=D
@SP
M=M+1 // end push pointer 1 (L9)
@SP // ==== add ====
A=M-1
D=M
A=A-1
M=D+M
@SP
M=M-1 // end add (L10)
@THIS // this 2
D=M
@2 // write 2 to A
D=D+A // D = segment+index
@R13 // save it to R13
M=D // write @THIS+2 to R13
@R13
A=M
D=M
@SP
A=M
M=D
@SP
M=M+1 // end push this 2 (L11)
@SP // ==== sub ====
A=M-1
D=M
A=A-1
M=M-D
@SP
M=M-1 // end sub (L12)
@THAT // that 6
D=M
@6 // write 6 to A
D=D+A // D = segment+index
@R13 // save it to R13
M=D // write @THAT+6 to R13
@R13
A=M
D=M
@SP
A=M
M=D
@SP
M=M+1 // end push that 6 (L13)
@SP // ==== add ====
A=M-1
D=M
A=A-1
M=D+M
@SP
M=M-1 // end add (L14)
@126
0;JMP

@ -0,0 +1,2 @@
|RAM[256]| RAM[3] | RAM[4] |RAM[3032|RAM[3046|
| 6084 | 3030 | 3040 | 32 | 46 |

@ -185,6 +185,14 @@ class CodeWriter {
]);
break;
case 'pointer':
$register = $this->resolvePointer($index);
$this->write([
"$register // pointer $index",
"D=M"
]);
break;
case 'temp':
$register = $this->resolveTemp($index);
$this->write([
@ -255,6 +263,18 @@ class CodeWriter {
]);
break;
case 'pointer':
// pointer points to a 2 register segment holding [this, that]
$register = $this->resolvePointer($index);
$this->write([
"@SP // pop",
"AM=M-1",
"D=M",
$register,
"M=D // (L{$this->sourceLine})"
]);
break;
case 'temp':
$tempRegister = $this->resolveTemp($index);
$this->write([
@ -271,6 +291,10 @@ class CodeWriter {
}
}
private function resolvePointer(Int $index) {
return $index == 0 ? '@THIS' : '@THAT';
}
// Keeping this because book asked me to
function writePushPop(Int $command, String $segment , Int $index) {
switch ($command) {

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