diff options
Diffstat (limited to 'src/pkg/runtime/memmove_386.s')
| -rw-r--r-- | src/pkg/runtime/memmove_386.s | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/src/pkg/runtime/memmove_386.s b/src/pkg/runtime/memmove_386.s new file mode 100644 index 0000000000..f7bc402590 --- /dev/null +++ b/src/pkg/runtime/memmove_386.s @@ -0,0 +1,65 @@ + TEXT memmove(SB), $0 + + MOVL to+0(FP), DI + MOVL fr+4(FP), SI + MOVL n+8(FP), BX + JLT fault + +/* + * check and set for backwards + * should we look closer for overlap? + */ + CMPL SI, DI + JLS back + +/* + * foreward copy loop + */ + MOVL BX, CX + SHRL $2, CX + ANDL $3, BX + + REP; MOVSL + MOVL BX, CX + REP; MOVSB + + MOVL to+0(FP),AX + RET +/* + * whole thing backwards has + * adjusted addresses + */ +back: + ADDL BX, DI + ADDL BX, SI + STD + +/* + * copy + */ + MOVL BX, CX + SHRL $2, CX + ANDL $3, BX + + SUBL $4, DI + SUBL $4, SI + REP; MOVSL + + ADDL $3, DI + ADDL $3, SI + MOVL BX, CX + REP; MOVSB + + CLD + MOVL to+0(FP),AX + RET + +/* + * if called with negative count, + * treat as error rather than + * rotating all of memory + */ +fault: + MOVL $0,SI + MOVL 0(SI), AX + RET |