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topher6345/arithmetic.asm

Last active August 29, 2015 14:03
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Various Algorithms to swap variables in Simplified assembly
Raw
arithmetic.asm
; Swap Registers A & B with no tmp
JMP start
ARG1: DB 13 ; Variable
ARG2: DB 3 ; Variable
start:
MOV A, [ARG1] ; A = ARG1;
MOV B, [ARG2] ; B = ARG2;
call swap
DB 0 ; exit();
swap: ; swap(A,B)
SUB A, B ; a = a - b
ADD B, A ; b = a + b
SUB B, A ; b = b - a
RET
Raw
with_tmp.asm
; Swap Registers A & B with tmp
JMP start
ARG1: DB 13 ; Variable
ARG2: DB 3 ; Variable
start:
MOV A, [ARG1] ; A = ARG1;
MOV B, [ARG2] ; B = ARG2;
call swap
DB 0 ; exit();
swap: ; swap(A,B)
MOV C, A
MOV A, B
MOV B, C
RET
Raw
xor.asm
; Swap Registers A & B with XOR
JMP start
ARG1: DB 13 ; Variable
ARG2: DB 3 ; Variable
start:
MOV A, [ARG1] ; A = ARG1;
MOV B, [ARG2] ; B = ARG2;
call swap
DB 0 ; exit();
swap: ; swap(A,B)
XOR A, B ; a = a ^ b
XOR A, B ; a = a ^ b
XOR B, A ; b = b ^ a
XOR B, A ; b = b ^ b
RET
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