diff options
| author | Taru Karttunen <taruti@taruti.net> | 2011-03-30 15:46:40 +0300 |
|---|---|---|
| committer | Taru Karttunen <taruti@taruti.net> | 2011-03-30 15:46:40 +0300 |
| commit | e5888a1ffdae813d7575f5fb02275c6bb07e5199 (patch) | |
| tree | d8d51eac403f07814b9e936eed0c9a79195e2450 /sys/src/libc/68000/memmove.s | |
Import sources from 2011-03-30 iso image
Diffstat (limited to 'sys/src/libc/68000/memmove.s')
| -rwxr-xr-x | sys/src/libc/68000/memmove.s | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/sys/src/libc/68000/memmove.s b/sys/src/libc/68000/memmove.s new file mode 100755 index 000000000..618e368d3 --- /dev/null +++ b/sys/src/libc/68000/memmove.s @@ -0,0 +1,120 @@ + TEXT memmove(SB), $0 + + MOVL n+8(FP), R0 /* count */ + BEQ return + BGT ok + MOVL 0, R0 +ok: + MOVL s1+0(FP), A2 /* dest pointer */ + MOVL s2+4(FP), A1 /* source pointer */ + + CMPL A2,A1 + BHI back + +/* + * byte-at-a-time foreward copy to + * get source (A1) alligned. + */ +f1: + MOVL A1, R1 + ANDL $3, R1 + BEQ f2 + SUBL $1, R0 + BLT return + MOVB (A1)+, (A2)+ + BRA f1 + +/* + * check that dest is alligned + * if not, just go byte-at-a-time + */ +f2: + MOVL A2, R1 + ANDL $3, R1 + BEQ f3 + SUBL $1, R0 + BLT return + BRA f5 +/* + * quad-long-at-a-time forward copy + */ +f3: + SUBL $16, R0 + BLT f4 + MOVL (A1)+, (A2)+ + MOVL (A1)+, (A2)+ + MOVL (A1)+, (A2)+ + MOVL (A1)+, (A2)+ + BRA f3 + +/* + * cleanup byte-at-a-time + */ +f4: + ADDL $15, R0 + BLT return +f5: + MOVB (A1)+, (A2)+ + SUBL $1, R0 + BGE f5 + BRA return + +return: + MOVL s1+0(FP),R0 + RTS + +/* + * everything the same, but + * copy backwards + */ +back: + ADDL R0, A1 + ADDL R0, A2 + +/* + * byte-at-a-time backward copy to + * get source (A1) alligned. + */ +b1: + MOVL A1, R1 + ANDL $3, R1 + BEQ b2 + SUBL $1, R0 + BLT return + MOVB -(A1), -(A2) + BRA b1 + +/* + * check that dest is alligned + * if not, just go byte-at-a-time + */ +b2: + MOVL A2, R1 + ANDL $3, R1 + BEQ b3 + SUBL $1, R0 + BLT return + BRA b5 +/* + * quad-long-at-a-time backward copy + */ +b3: + SUBL $16, R0 + BLT b4 + MOVL -(A1), -(A2) + MOVL -(A1), -(A2) + MOVL -(A1), -(A2) + MOVL -(A1), -(A2) + BRA b3 + +/* + * cleanup byte-at-a-time backward + */ +b4: + ADDL $15, R0 + BLT return +b5: + MOVB -(A1), -(A2) + SUBL $1, R0 + BGE b5 + BRA return |