diff options
Diffstat (limited to 'sysdeps/i386/stpncpy.S')
| -rw-r--r-- | sysdeps/i386/stpncpy.S | 54 |
1 files changed, 27 insertions, 27 deletions
diff --git a/sysdeps/i386/stpncpy.S b/sysdeps/i386/stpncpy.S index 96878fb79a..e0213082f8 100644 --- a/sysdeps/i386/stpncpy.S +++ b/sysdeps/i386/stpncpy.S @@ -1,7 +1,7 @@ -/* stpncpy -- copy no more then N bytes from SRC to DEST, returning the - address of the terminating '\0' in DEST. +/* copy no more then N bytes from SRC to DEST, returning the address of + the terminating '\0' in DEST. For Intel 80x86, x>=3. - Copyright (C) 1994, 1995, 1996 Free Software Foundation, Inc. + Copyright (C) 1994, 1995, 1996, 1997 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu> Some bug fixes by Alan Modra <Alan@SPRI.Levels.UniSA.Edu.Au> @@ -45,98 +45,98 @@ ENTRY (__stpncpy) subl %eax, %esi /* magic: reduce number of loop variants to one using addressing mode */ - jmp L1 /* jump to loop "head" */ + jmp L(1) /* jump to loop "head" */ ALIGN(4) /* Four times unfolded loop with two loop counters. We get the the third value (the source address) by using the index+base addressing mode. */ -L2: movb (%eax,%esi), %dl /* load current char */ +L(2): movb (%eax,%esi), %dl /* load current char */ movb %dl, (%eax) /* and store it */ testb %dl, %dl /* was it NUL? */ - jz L7 /* yes, then exit */ + jz L(7) /* yes, then exit */ movb 1(%eax,%esi), %dl /* load current char */ movb %dl, 1(%eax) /* and store it */ testb %dl, %dl /* was it NUL? */ - jz L6 /* yes, then exit */ + jz L(6) /* yes, then exit */ movb 2(%eax,%esi), %dl /* load current char */ movb %dl, 2(%eax) /* and store it */ testb %dl, %dl /* was it NUL? */ - jz L5 /* yes, then exit */ + jz L(5) /* yes, then exit */ movb 3(%eax,%esi), %dl /* load current char */ movb %dl, 3(%eax) /* and store it */ testb %dl, %dl /* was it NUL? */ - jz L4 /* yes, then exit */ + jz L(4) /* yes, then exit */ addl $4, %eax /* increment loop counter for full round */ -L1: subl $4, %ecx /* still more than 4 bytes allowed? */ - jae L2 /* yes, then go to start of loop */ +L(1): subl $4, %ecx /* still more than 4 bytes allowed? */ + jae L(2) /* yes, then go to start of loop */ /* The maximal remaining 15 bytes are not processed in a loop. */ addl $4, %ecx /* correct above subtraction */ - jz L9 /* maximal allowed char reached => go to end */ + jz L(9) /* maximal allowed char reached => go to end */ movb (%eax,%esi), %dl /* load current char */ movb %dl, (%eax) /* and store it */ testb %dl, %dl /* was it NUL? */ - jz L3 /* yes, then exit */ + jz L(3) /* yes, then exit */ incl %eax /* increment pointer */ decl %ecx /* decrement length counter */ - jz L9 /* no more allowed => exit */ + jz L(9) /* no more allowed => exit */ movb (%eax,%esi), %dl /* load current char */ movb %dl, (%eax) /* and store it */ testb %dl, %dl /* was it NUL? */ - jz L3 /* yes, then exit */ + jz L(3) /* yes, then exit */ incl %eax /* increment pointer */ decl %ecx /* decrement length counter */ - jz L9 /* no more allowed => exit */ + jz L(9) /* no more allowed => exit */ movb (%eax,%esi), %dl /* load current char */ movb %dl, (%eax) /* and store it */ testb %dl, %dl /* was it NUL? */ - jz L3 /* yes, then exit */ + jz L(3) /* yes, then exit */ incl %eax /* increment pointer */ - jmp L9 /* we don't have to test for counter underflow + jmp L(9) /* we don't have to test for counter underflow because we know we had a most 3 bytes remaining => exit */ /* When coming from the main loop we have to adjust the pointer. */ -L4: decl %ecx /* decrement counter */ +L(4): decl %ecx /* decrement counter */ incl %eax /* increment pointer */ -L5: decl %ecx /* increment pointer */ +L(5): decl %ecx /* increment pointer */ incl %eax /* increment pointer */ -L6: decl %ecx /* increment pointer */ +L(6): decl %ecx /* increment pointer */ incl %eax /* increment pointer */ -L7: +L(7): addl $3, %ecx /* correct pre-decrementation of counter at the beginning of the loop; but why 3 and not 4? Very simple, we have to count the NUL char we already wrote. */ - jz L9 /* counter is also 0 => exit */ + jz L(9) /* counter is also 0 => exit */ /* We now have to fill the rest of the buffer with NUL. This is done in a tricky way. Please note that the addressing mode used below is not the same we used above. Here we use the %ecx register. */ -L8: +L(8): movb $0, (%ecx,%eax) /* store NUL char */ -L3: decl %ecx /* all bytes written? */ - jnz L8 /* no, then again */ +L(3): decl %ecx /* all bytes written? */ + jnz L(8) /* no, then again */ -L9: popl %esi /* restore saved register content */ +L(9): popl %esi /* restore saved register content */ ret END (__stpncpy) |