diff options
Diffstat (limited to 'newlib/libc/machine/i386/memmove.S')
-rw-r--r-- | newlib/libc/machine/i386/memmove.S | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/newlib/libc/machine/i386/memmove.S b/newlib/libc/machine/i386/memmove.S new file mode 100644 index 00000000000..a89a296f7e5 --- /dev/null +++ b/newlib/libc/machine/i386/memmove.S @@ -0,0 +1,145 @@ +/* + * ==================================================== + * Copyright (C) 1998 by Cygnus Solutions. All rights reserved. + * + * Permission to use, copy, modify, and distribute this + * software is freely granted, provided that this notice + * is preserved. + * ==================================================== + */ + + #include "i386mach.h" + + .global SYM (memmove) + +SYM (memmove): + + pushl ebp + movl esp,ebp + pushl esi + pushl edi + pushl ebx + movl 8(ebp),edi + movl 16(ebp),ecx + movl 12(ebp),esi + +/* check for destructive overlap (src < dst && dst < src + length) */ + + cld + cmpl edi,esi + jae .L2 + leal -1(ecx,esi),ebx + cmpl ebx,edi + ja .L2 + +/* IF: destructive overlap, must copy backwards */ + + addl ecx,esi + addl ecx,edi + std + +#ifndef __OPTIMIZE_SIZE__ + + cmpl $8,ecx + jbe .L13 +.L18: + +/* move trailing bytes in reverse until destination address is long word aligned */ + + movl edi,edx + movl ecx,ebx + andl $3,edx + jz .L21 + + movl edx,ecx + decl esi + decl edi + subl ecx,ebx + rep + movsb + + mov ebx,ecx + incl esi + incl edi + +.L21: + +/* move bytes in reverse, a long word at a time */ + + shrl $2,ecx + subl $4,esi + subl $4,edi + rep + movsl + + addl $4,esi + addl $4,edi + movl ebx,ecx + andl $3,ecx + +#endif /* !__OPTIMIZE_SIZE__ */ + +/* handle any remaining bytes not on a long word boundary */ + +.L13: + decl esi + decl edi + +.L15: + rep + movsb + jmp .L5 + .p2align 4,,7 + +/* ELSE: no destructive overlap so we copy forwards */ + +.L2: + +#ifndef __OPTIMIZE_SIZE__ + + cmpl $8,ecx + jbe .L3 + +/* move any preceding bytes until destination address is long word aligned */ + + movl edi,edx + movl ecx,ebx + andl $3,edx + jz .L11 + movl $4,ecx + subl edx,ecx + andl $3,ecx + subl ecx,ebx + rep + movsb + + mov ebx,ecx + +/* move bytes a long word at a time */ + +.L11: + shrl $2,ecx + .p2align 2 + rep + movsl + + movl ebx,ecx + andl $3,ecx + +#endif /* !__OPTIMIZE_SIZE__ */ + +/* handle any remaining bytes */ + +.L3: + rep + movsb +.L5: + movl 8(ebp),eax + cld + + leal -12(ebp),esp + popl ebx + popl edi + popl esi + leave + ret |