project 7: pass the test of StackTest

nand2tetris/projects/7/StackArithmetic/StackTest/StackTest.asm

@@ -25,6 +25,8 @@ D=M-D
 M=-1
 @END_EQUAL_ID_25
 D;JEQ
+@SP
+A=M-1
 M=0
 (END_EQUAL_ID_25)
 // push constant 17
@@ -52,10 +54,12 @@ D=M
 A=M-1
 D=M-D
 M=-1
-@END_EQUAL_ID_54
+@END_EQUAL_ID_56
 D;JEQ
+@SP
+A=M-1
 M=0
-(END_EQUAL_ID_54)
+(END_EQUAL_ID_56)
 // push constant 16
 @16
 D=A
@@ -81,10 +85,12 @@ D=M
 A=M-1
 D=M-D
 M=-1
-@END_EQUAL_ID_83
+@END_EQUAL_ID_87
 D;JEQ
+@SP
+A=M-1
 M=0
-(END_EQUAL_ID_83)
+(END_EQUAL_ID_87)
 // push constant 892
 @892
 D=A
@@ -110,10 +116,12 @@ D=M
 A=M-1
 D=M-D
 M=-1
-@END_LT_ID_112
+@END_LT_ID_118
 D;JLT
+@SP
+A=M-1
 M=0
-(END_LT_ID_112)
+(END_LT_ID_118)
 // push constant 891
 @891
 D=A
@@ -139,10 +147,12 @@ D=M
 A=M-1
 D=M-D
 M=-1
-@END_LT_ID_141
+@END_LT_ID_149
 D;JLT
+@SP
+A=M-1
 M=0
-(END_LT_ID_141)
+(END_LT_ID_149)
 // push constant 891
 @891
 D=A
@@ -168,10 +178,12 @@ D=M
 A=M-1
 D=M-D
 M=-1
-@END_LT_ID_170
+@END_LT_ID_180
 D;JLT
+@SP
+A=M-1
 M=0
-(END_LT_ID_170)
+(END_LT_ID_180)
 // push constant 32767
 @32767
 D=A
@@ -197,10 +209,12 @@ D=M
 A=M-1
 D=M-D
 M=-1
-@END_GT_ID_199
+@END_GT_ID_211
 D;JGT
+@SP
+A=M-1
 M=0
-(END_GT_ID_199)
+(END_GT_ID_211)
 // push constant 32766
 @32766
 D=A
@@ -226,10 +240,12 @@ D=M
 A=M-1
 D=M-D
 M=-1
-@END_GT_ID_228
+@END_GT_ID_242
 D;JGT
+@SP
+A=M-1
 M=0
-(END_GT_ID_228)
+(END_GT_ID_242)
 // push constant 32766
 @32766
 D=A
@@ -255,10 +271,12 @@ D=M
 A=M-1
 D=M-D
 M=-1
-@END_GT_ID_257
+@END_GT_ID_273
 D;JGT
+@SP
+A=M-1
 M=0
-(END_GT_ID_257)
+(END_GT_ID_273)
 // push constant 57
 @57
 D=A

nand2tetris/projects/7/StackArithmetic/StackTest/StackTest.out

@@ -0,0 +1,4 @@
+|  RAM[0]  | RAM[256] | RAM[257] | RAM[258] | RAM[259] | RAM[260] |
+|     266  |      -1  |       0  |       0  |       0  |      -1  |
+| RAM[261] | RAM[262] | RAM[263] | RAM[264] | RAM[265] |
+|       0  |      -1  |       0  |       0  |     -91  |

nand2tetris/projects/7/my_vm/code_writer.py

@@ -17,6 +17,7 @@ def writeArithmetic(self, command: str):
             self.output.append('A=M\n')
             self.output.append('D=M\n')
             # get the 1st operand from the top of the stack and you can refer to it using the M register
+            # Caution: I actually don't decrease the stack pointer here when getting the 1st operand
             self.output.append('@SP\n')
             self.output.append('A=M-1\n')
         elif command in UNARY_OPEARATORS:
@@ -39,6 +40,11 @@ def writeArithmetic(self, command: str):
             current_id_of_eq_command = len(self.output)
             self.output.append(f'@END_EQUAL_ID_{current_id_of_eq_command}\n')
             self.output.append('D;JEQ\n')
+            ## ======== Caution: you need to assign SP-1 to A register "again" in case the A register has been modified by the previous command, 
+            # if the A register has been modified by the previous command, then the M register contains some unkown value, so we need to assign SP-1 to A register again
+            self.output.append('@SP\n')
+            self.output.append('A=M-1\n')
+            ## =========
             self.output.append('M=0\n')
             self.output.append(f'(END_EQUAL_ID_{current_id_of_eq_command})\n')
         elif command == 'gt':
@@ -51,6 +57,11 @@ def writeArithmetic(self, command: str):
             current_id_of_gt_command = len(self.output)
             self.output.append(f'@END_GT_ID_{current_id_of_gt_command}\n')
             self.output.append('D;JGT\n')
+            ## ======== Caution: you need to assign SP-1 to A register "again" in case the A register has been modified by the previous command, 
+            # if the A register has been modified by the previous command, then the M register contains some unkown value, so we need to assign SP-1 to A register again
+            self.output.append('@SP\n')
+            self.output.append('A=M-1\n')
+            ## =========
             self.output.append('M=0\n')
             self.output.append(f'(END_GT_ID_{current_id_of_gt_command})\n')
         elif command == 'lt':
@@ -63,6 +74,11 @@ def writeArithmetic(self, command: str):
             current_id_of_lt_command = len(self.output)
             self.output.append(f'@END_LT_ID_{current_id_of_lt_command}\n')
             self.output.append('D;JLT\n')
+            ## ======== Caution: you need to assign SP-1 to A register "again" in case the A register has been modified by the previous command, 
+            # if the A register has been modified by the previous command, then the M register contains some unkown value, so we need to assign SP-1 to A register again
+            self.output.append('@SP\n')
+            self.output.append('A=M-1\n')
+            ## =========            
             self.output.append('M=0\n')
             self.output.append(f'(END_LT_ID_{current_id_of_lt_command})\n')
         else:

nand2tetris/projects/7/my_vm/vm_translator.py

@@ -28,6 +28,7 @@ def translate(self):
 
 if __name__ == '__main__':
     # python -m my_vm.vm_translator  ./StackArithmetic/SimpleAdd/SimpleAdd.vm
+    # python -m my_vm.vm_translator  ./StackArithmetic/StackTest/StackTest.vm
     import sys
     if len(sys.argv) != 2:
         print('Please provide a VM file.')