From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: 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! --- arch/alpha/lib/ev67-strlen.S | 49 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) create mode 100644 arch/alpha/lib/ev67-strlen.S (limited to 'arch/alpha/lib/ev67-strlen.S') diff --git a/arch/alpha/lib/ev67-strlen.S b/arch/alpha/lib/ev67-strlen.S new file mode 100644 index 000000000000..503928072523 --- /dev/null +++ b/arch/alpha/lib/ev67-strlen.S @@ -0,0 +1,49 @@ +/* + * arch/alpha/lib/ev67-strlen.S + * 21264 version by Rick Gorton + * + * Finds length of a 0-terminated string. Optimized for the + * Alpha architecture: + * + * - memory accessed as aligned quadwords only + * - uses bcmpge to compare 8 bytes in parallel + * + * 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 + */ + + .set noreorder + .set noat + + .globl strlen + .ent strlen + .align 4 +strlen: + ldq_u $1, 0($16) # L : load first quadword ($16 may be misaligned) + lda $2, -1($31) # E : + insqh $2, $16, $2 # U : + andnot $16, 7, $0 # E : + + or $2, $1, $1 # E : + cmpbge $31, $1, $2 # E : $2 <- bitmask: bit i == 1 <==> i-th byte == 0 + nop # E : + bne $2, $found # U : + +$loop: ldq $1, 8($0) # L : + addq $0, 8, $0 # E : addr += 8 + cmpbge $31, $1, $2 # E : + beq $2, $loop # U : + +$found: + cttz $2, $3 # U0 : + addq $0, $3, $0 # E : + subq $0, $16, $0 # E : + ret $31, ($26) # L0 : + + .end strlen -- cgit v1.2.3