108 lines
2.1 KiB
NASM
108 lines
2.1 KiB
NASM
; memory copy/compare routines
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; copy specified number of bytes from source pointer to destination pointer
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; if the source and destination overlap, the behavior is undefined
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; inputs:
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; r0: pointer to source
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; r1: pointer to destination
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; r2: number of bytes to copy
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; outputs:
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; none
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copy_memory_bytes:
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push r0
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push r1
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push r31
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mov r31, r2
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copy_memory_bytes_loop:
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mov.8 [r1], [r0]
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inc r0
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inc r1
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loop copy_memory_bytes_loop
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pop r31
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pop r1
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pop r0
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ret
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; copy specified number of words from source pointer to destination pointer
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; if the source and destination overlap, the behavior is undefined
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; inputs:
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; r0: pointer to source
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; r1: pointer to destination
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; r2: number of words to copy
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; outputs:
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; none
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copy_memory_words:
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push r0
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push r1
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push r31
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mov r31, r2
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copy_memory_words_loop:
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mov [r1], [r0]
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add r0, 4
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add r1, 4
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loop copy_memory_words_loop
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pop r31
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pop r1
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pop r0
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ret
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; compare specified number of bytes from source pointer with destination pointer
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; inputs:
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; r0: pointer to source
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; r1: pointer to destination
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; r2: number of bytes to compare
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; outputs:
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; Z flag
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compare_memory_bytes:
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push r0
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push r1
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push r31
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mov r31, r2
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compare_memory_bytes_loop:
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cmp.8 [r1], [r0]
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ifnz jmp compare_memory_bytes_not_equal
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inc r0
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inc r1
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loop compare_memory_bytes_loop
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; set Z flag if we reach this point
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mov r0, 0
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cmp r0, 0
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compare_memory_bytes_not_equal:
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pop r31
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pop r1
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pop r0
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ret
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; compare specified number of words from source pointer with destination pointer
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; inputs:
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; r0: pointer to source
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; r1: pointer to destination
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; r2: number of words to compare
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; outputs:
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; Z flag
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compare_memory_words:
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push r0
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push r1
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push r31
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mov r31, r2
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compare_memory_words_loop:
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cmp [r1], [r0]
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ifnz jmp compare_memory_words_not_equal
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add r0, 4
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add r1, 4
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loop compare_memory_words_loop
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; set Z flag if we reach this point
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mov r0, 0
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cmp r0, 0
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compare_memory_words_not_equal:
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pop r31
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pop r1
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pop r0
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ret
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