forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
72 lines
2.0 KiB
72 lines
2.0 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
|
/* |
|
* arch/alpha/lib/strchr.S |
|
* Contributed by Richard Henderson (rth@tamu.edu) |
|
* |
|
* Return the address of a given character within a null-terminated |
|
* string, or null if it is not found. |
|
*/ |
|
#include <asm/export.h> |
|
#include <asm/regdef.h> |
|
|
|
.set noreorder |
|
.set noat |
|
|
|
.align 3 |
|
.globl strchr |
|
.ent strchr |
|
strchr: |
|
.frame sp, 0, ra |
|
.prologue 0 |
|
|
|
zapnot a1, 1, a1 # e0 : zero extend the search character |
|
ldq_u t0, 0(a0) # .. e1 : load first quadword |
|
sll a1, 8, t5 # e0 : replicate the search character |
|
andnot a0, 7, v0 # .. e1 : align our loop pointer |
|
or t5, a1, a1 # e0 : |
|
lda t4, -1 # .. e1 : build garbage mask |
|
sll a1, 16, t5 # e0 : |
|
cmpbge zero, t0, t2 # .. e1 : bits set iff byte == zero |
|
mskqh t4, a0, t4 # e0 : |
|
or t5, a1, a1 # .. e1 : |
|
sll a1, 32, t5 # e0 : |
|
cmpbge zero, t4, t4 # .. e1 : bits set iff byte is garbage |
|
or t5, a1, a1 # e0 : |
|
xor t0, a1, t1 # .. e1 : make bytes == c zero |
|
cmpbge zero, t1, t3 # e0 : bits set iff byte == c |
|
or t2, t3, t0 # e1 : bits set iff char match or zero match |
|
andnot t0, t4, t0 # e0 : clear garbage bits |
|
bne t0, $found # .. e1 (zdb) |
|
|
|
$loop: ldq t0, 8(v0) # e0 : |
|
addq v0, 8, v0 # .. e1 : |
|
nop # e0 : |
|
xor t0, a1, t1 # .. e1 (ev5 data stall) |
|
cmpbge zero, t0, t2 # e0 : bits set iff byte == 0 |
|
cmpbge zero, t1, t3 # .. e1 : bits set iff byte == c |
|
or t2, t3, t0 # e0 : |
|
beq t0, $loop # .. e1 (zdb) |
|
|
|
$found: negq t0, t1 # e0 : clear all but least set bit |
|
and t0, t1, t0 # e1 (stall) |
|
|
|
and t0, t3, t1 # e0 : bit set iff byte was the char |
|
beq t1, $retnull # .. e1 (zdb) |
|
|
|
and t0, 0xf0, t2 # e0 : binary search for that set bit |
|
and t0, 0xcc, t3 # .. e1 : |
|
and t0, 0xaa, t4 # e0 : |
|
cmovne t2, 4, t2 # .. e1 : |
|
cmovne t3, 2, t3 # e0 : |
|
cmovne t4, 1, t4 # .. e1 : |
|
addq t2, t3, t2 # e0 : |
|
addq v0, t4, v0 # .. e1 : |
|
addq v0, t2, v0 # e0 : |
|
ret # .. e1 : |
|
|
|
$retnull: |
|
mov zero, v0 # e0 : |
|
ret # .. e1 : |
|
|
|
.end strchr |
|
EXPORT_SYMBOL(strchr)
|
|
|