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from .utils import *
# template for lt, gt, and eq
COMPARE_ASM = """@SP
AM=M-1
D=M
A=A-1
D=M-D
M=0
@END_{tag}
D;{jmp}
@SP
A=M-1
M=-1
(END_{tag})
"""
# exact complement of VM command which leaves top of stack false
JMP = {
"lt": "JGE",
"eq": "JNE",
"gt": "JLE",
}
tag_idx = 0
def translate_compare(command, verbose=False):
global tag_idx
asm = f"// {command}\n" if verbose else ""
asm += COMPARE_ASM.format(tag=f"{command.upper()}_{tag_idx}", jmp=JMP[command])
tag_idx += 1
return asm
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