1/* 2 * arch/alpha/lib/strchr.S 3 * Contributed by Richard Henderson (rth@tamu.edu) 4 * 5 * Return the address of a given character within a null-terminated 6 * string, or null if it is not found. 7 */ 8 9#include <asm/regdef.h> 10 11 .set noreorder 12 .set noat 13 14 .align 3 15 .globl strchr 16 .ent strchr 17strchr: 18 .frame sp, 0, ra 19 .prologue 0 20 21 zapnot a1, 1, a1 # e0 : zero extend the search character 22 ldq_u t0, 0(a0) # .. e1 : load first quadword 23 sll a1, 8, t5 # e0 : replicate the search character 24 andnot a0, 7, v0 # .. e1 : align our loop pointer 25 or t5, a1, a1 # e0 : 26 lda t4, -1 # .. e1 : build garbage mask 27 sll a1, 16, t5 # e0 : 28 cmpbge zero, t0, t2 # .. e1 : bits set iff byte == zero 29 mskqh t4, a0, t4 # e0 : 30 or t5, a1, a1 # .. e1 : 31 sll a1, 32, t5 # e0 : 32 cmpbge zero, t4, t4 # .. e1 : bits set iff byte is garbage 33 or t5, a1, a1 # e0 : 34 xor t0, a1, t1 # .. e1 : make bytes == c zero 35 cmpbge zero, t1, t3 # e0 : bits set iff byte == c 36 or t2, t3, t0 # e1 : bits set iff char match or zero match 37 andnot t0, t4, t0 # e0 : clear garbage bits 38 bne t0, $found # .. e1 (zdb) 39 40$loop: ldq t0, 8(v0) # e0 : 41 addq v0, 8, v0 # .. e1 : 42 nop # e0 : 43 xor t0, a1, t1 # .. e1 (ev5 data stall) 44 cmpbge zero, t0, t2 # e0 : bits set iff byte == 0 45 cmpbge zero, t1, t3 # .. e1 : bits set iff byte == c 46 or t2, t3, t0 # e0 : 47 beq t0, $loop # .. e1 (zdb) 48 49$found: negq t0, t1 # e0 : clear all but least set bit 50 and t0, t1, t0 # e1 (stall) 51 52 and t0, t3, t1 # e0 : bit set iff byte was the char 53 beq t1, $retnull # .. e1 (zdb) 54 55 and t0, 0xf0, t2 # e0 : binary search for that set bit 56 and t0, 0xcc, t3 # .. e1 : 57 and t0, 0xaa, t4 # e0 : 58 cmovne t2, 4, t2 # .. e1 : 59 cmovne t3, 2, t3 # e0 : 60 cmovne t4, 1, t4 # .. e1 : 61 addq t2, t3, t2 # e0 : 62 addq v0, t4, v0 # .. e1 : 63 addq v0, t2, v0 # e0 : 64 ret # .. e1 : 65 66$retnull: 67 mov zero, v0 # e0 : 68 ret # .. e1 : 69 70 .end strchr 71