diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/alpha/lib/ev67-strcat.S |
Linux-2.6.12-rc2v2.6.12-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/ev67-strcat.S')
-rw-r--r-- | arch/alpha/lib/ev67-strcat.S | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/arch/alpha/lib/ev67-strcat.S b/arch/alpha/lib/ev67-strcat.S new file mode 100644 index 00000000000..c426fe3ed72 --- /dev/null +++ b/arch/alpha/lib/ev67-strcat.S @@ -0,0 +1,54 @@ +/* + * arch/alpha/lib/ev67-strcat.S + * 21264 version contributed by Rick Gorton <rick.gorton@alpha-processor.com> + * + * Append a null-terminated string from SRC to DST. + * + * Much of the information about 21264 scheduling/coding comes from: + * Compiler Writer's Guide for the Alpha 21264 + * abbreviated as 'CWG' in other comments here + * ftp.digital.com/pub/Digital/info/semiconductor/literature/dsc-library.html + * Scheduling notation: + * E - either cluster + * U - upper subcluster; U0 - subcluster U0; U1 - subcluster U1 + * L - lower subcluster; L0 - subcluster L0; L1 - subcluster L1 + * Try not to change the actual algorithm if possible for consistency. + * Commentary: It seems bogus to walk the input string twice - once + * to determine the length, and then again while doing the copy. + * A significant (future) enhancement would be to only read the input + * string once. + */ + + + .text + + .align 4 + .globl strcat + .ent strcat +strcat: + .frame $30, 0, $26 + .prologue 0 + + mov $16, $0 # E : set up return value + /* Find the end of the string. */ + ldq_u $1, 0($16) # L : load first quadword (a0 may be misaligned) + lda $2, -1 # E : + insqh $2, $16, $2 # U : + + andnot $16, 7, $16 # E : + or $2, $1, $1 # E : + cmpbge $31, $1, $2 # E : bits set iff byte == 0 + bne $2, $found # U : + +$loop: ldq $1, 8($16) # L : + addq $16, 8, $16 # E : + cmpbge $31, $1, $2 # E : + beq $2, $loop # U : + +$found: cttz $2, $3 # U0 : + addq $16, $3, $16 # E : + /* Now do the append. */ + mov $26, $23 # E : + br __stxcpy # L0 : + + .end strcat |