OccupyMars2025
commented
1 month ago try to debug: It is most probable that the generared .asm file has bugs in it. So I regenerate nand2tetris/projects/8/FunctionCalls/SimpleFunction/SimpleFunction.asm, and test it, the result is as follows
Attention: the PC is 1151, but PC should be 132 or 133 at the end of execution
1. Use CPUEmulator to execute it one line per step, found that writeReturn() generated code @R14 is related to the bug
2. study the source code of def writeReturn(self)
3. find the bug, it has nothing to do with my code, in nand2tetris/projects/8/FunctionCalls/SimpleFunction/SimpleFunction.tst, the preconfiguration (lacking Sys.init) is NOT complete, there are no returnAddress, LCL, ARG, THIS, THAT of the caller saved in betweem the argument segment and the local segment, so in def writeReturn(self):, when you implement the part of # retAddr = *(frame-5) // puts the return address in a temporary variable, store it in R14 , you get a problem
set sp 317,
set local 317,
set argument 310,
set this 3000,
set that 4000,
set argument[0] 1234,
set argument[1] 37,
set argument[2] 9,
set argument[3] 305,
set argument[4] 300,
set argument[5] 3010,
set argument[6] 4010,4. temporary workaround: in in def writeReturn(self):, replace the original implementation of # retAddr = *(frame-5) // puts the return address in a temporary variable, store it in R14 with the following code
# original implementation
# retAddr = *(frame-5) // puts the return address in a temporary variable, store it in R14
self.output.append('@5\n')
self.output.append('D=A\n')
self.output.append('@R13\n')
self.output.append('A=M-D\n')
self.output.append('D=M\n')
self.output.append('@R14\n')
self.output.append('M=D\n')# modified implementation
# retAddr = *(frame-5) // puts the return address in a temporary variable, store it in R14
self.output.append('@END\n')
self.output.append('D=A\n')
self.output.append('@R14\n')
self.output.append('M=D\n')
commit: https://github.com/OccupyMars2025/Nand2Tetris/commit/dd9ce202eae687dfda1eac92c36f2f36a0be29c5