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| author | Frederick Yin <fkfd@fkfd.me> | 2022-08-23 23:40:41 +0800 |
|---|---|---|
| committer | Frederick Yin <fkfd@fkfd.me> | 2022-08-23 23:40:41 +0800 |
| commit | 1568a0caccc2c264a322dadf81bab16b68195f87 (patch) | |
| tree | 437c354bb7da052bff824f1d6b810cd7bc46425b | |
| parent | 488e3483148defb7ba3f63a26d23ee1e92a2a72f (diff) | |
hack-vm: fix assembly for function commands
| -rw-r--r-- | projects/hack-vm/function.py | 41 |
1 files changed, 23 insertions, 18 deletions
diff --git a/projects/hack-vm/function.py b/projects/hack-vm/function.py index 596c9cf..61c86f6 100644 --- a/projects/hack-vm/function.py +++ b/projects/hack-vm/function.py @@ -4,27 +4,27 @@ D=A A=M M=D @LCL -D=A +D=M @SP AM=M+1 M=D @ARG -D=A +D=M @SP AM=M+1 M=D @THIS -D=A +D=M @SP AM=M+1 M=D @THAT -D=A +D=M @SP AM=M+1 M=D @SP -DM=M+1 +MD=M+1 @LCL M=D @{arg_lcl_offset} @@ -36,22 +36,26 @@ M=D ({return_address}) """ -FUNCTION_ASM = """({function_label}) -@SP -A=M -M=0 -{init_vars}@SP -M=M+1 -""" +FUNCTION_ASM = "({function_label})\n" -# repeated for each local variable of function -INIT_VAR_ASM = """@SP +# repeated (n-1) times for function with n arguments +INIT_ONE_VAR_ASM = """@SP AM=M+1 M=0 """ -RETURN_ASM = """@ARG +# concatenated only when function has arguments +INIT_VARS_ASM = """@SP A=M +M=0 +{init_vars}@SP +M=M+1 +""" + +RETURN_ASM = """@LCL +D=M +@5 +A=D-A D=M @{tmp} M=D @@ -112,9 +116,10 @@ def translate_function(action, function, n, prog, verbose=False): function_label=f"{function}", ) else: - asm += FUNCTION_ASM.format( - function_label=f"{function}", init_vars=INIT_VAR_ASM * (n - 1) - ) + asm += FUNCTION_ASM.format(function_label=f"{function}") + if n > 0: + # function has arguments + asm += INIT_VARS_ASM.format(init_vars=INIT_ONE_VAR_ASM * (n - 1)) return asm |