49 lines
901 B
ArmAsm
49 lines
901 B
ArmAsm
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#include "defines.h"
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#ifdef __H8300H__
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.h8300h
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#endif
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#ifdef __H8300S__
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.h8300s
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#endif
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.global _memcpy
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_memcpy:
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; MOVP @(2/4,r7),A0P ; dst
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; MOVP @(4/8,r7),A1P ; src
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; MOVP @(6/12,r7),A2P ; len
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MOVP A0P,A3P ; keep copy of final dst
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ADDP A2P,A0P ; point to end of dst
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CMPP A0P,A3P ; see if anything to do
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beq quit
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ADDP A2P,A1P ; point to end of src
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; lets see if we can do this in words
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or A0L,A2L ; or in the dst address
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or A3L,A2L ; or the length
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or A1L,A2L ; or the src address
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btst #0,A2L ; see if the lsb is zero
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bne byteloop
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wordloop:
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subs #2,A1P ; point to word
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mov.w @A1P,A2 ; get word
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mov.w A2,@-A0P ; save word
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CMPP A0P,A3P ; at the front again ?
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bne wordloop
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rts
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byteloop:
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subs #1,A1P ; point to byte
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mov.b @A1P,A2L ; get byte
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mov.b A2L,@-A0P ; save byte
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CMPP A0P,A3P ; at the front again ?
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bne byteloop
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; return with A0 pointing to dst
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quit: rts
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