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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 22:20:36 (GMT) |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 22:20:36 (GMT) |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/alpha/lib/strncat.S | |
download | linux-fsl-qoriq-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.xz |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'arch/alpha/lib/strncat.S')
-rw-r--r-- | arch/alpha/lib/strncat.S | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/arch/alpha/lib/strncat.S b/arch/alpha/lib/strncat.S new file mode 100644 index 0000000..a827816 --- /dev/null +++ b/arch/alpha/lib/strncat.S @@ -0,0 +1,84 @@ +/* + * arch/alpha/lib/strncat.S + * Contributed by Richard Henderson (rth@tamu.edu) + * + * Append no more than COUNT characters from the null-terminated string SRC + * to the null-terminated string DST. Always null-terminate the new DST. + * + * This differs slightly from the semantics in libc in that we never write + * past count, whereas libc may write to count+1. This follows the generic + * implementation in lib/string.c and is, IMHO, more sensible. + */ + + .text + + .align 3 + .globl strncat + .ent strncat +strncat: + .frame $30, 0, $26 + .prologue 0 + + mov $16, $0 # set up return value + beq $18, $zerocount + + /* Find the end of the string. */ + + ldq_u $1, 0($16) # load first quadword ($16 may be misaligned) + lda $2, -1($31) + insqh $2, $16, $2 + andnot $16, 7, $16 + or $2, $1, $1 + cmpbge $31, $1, $2 # bits set iff byte == 0 + bne $2, $found + +$loop: ldq $1, 8($16) + addq $16, 8, $16 + cmpbge $31, $1, $2 + beq $2, $loop + +$found: negq $2, $3 # clear all but least set bit + and $2, $3, $2 + + and $2, 0xf0, $3 # binary search for that set bit + and $2, 0xcc, $4 + and $2, 0xaa, $5 + cmovne $3, 4, $3 + cmovne $4, 2, $4 + cmovne $5, 1, $5 + addq $3, $4, $3 + addq $16, $5, $16 + addq $16, $3, $16 + + /* Now do the append. */ + + bsr $23, __stxncpy + + /* Worry about the null termination. */ + + zapnot $1, $27, $2 # was last byte a null? + bne $2, 0f + ret + +0: cmplt $27, $24, $2 # did we fill the buffer completely? + or $2, $18, $2 + bne $2, 2f + + and $24, 0x80, $2 # no zero next byte + bne $2, 1f + + /* Here there are bytes left in the current word. Clear one. */ + addq $24, $24, $24 # end-of-count bit <<= 1 +2: zap $1, $24, $1 + stq_u $1, 0($16) + ret + +1: /* Here we must read the next DST word and clear the first byte. */ + ldq_u $1, 8($16) + zap $1, 1, $1 + stq_u $1, 8($16) + +$zerocount: + ret + + .end strncat |