diff options
Diffstat (limited to 'arch/sparc/lib/memscan.S')
| -rw-r--r-- | arch/sparc/lib/memscan.S | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/arch/sparc/lib/memscan.S b/arch/sparc/lib/memscan.S new file mode 100644 index 00000000000..28e78ff090a --- /dev/null +++ b/arch/sparc/lib/memscan.S @@ -0,0 +1,133 @@ +/* $Id: memscan.S,v 1.4 1996/09/08 02:01:20 davem Exp $ + * memscan.S: Optimized memscan for the Sparc. + * + * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu) + */ + +/* In essence, this is just a fancy strlen. */ + +#define LO_MAGIC 0x01010101 +#define HI_MAGIC 0x80808080 + + .text + .align 4 + .globl __memscan_zero, __memscan_generic + .globl memscan +__memscan_zero: + /* %o0 = addr, %o1 = size */ + cmp %o1, 0 + bne,a 1f + andcc %o0, 3, %g0 + + retl + nop + +1: + be mzero_scan_word + sethi %hi(HI_MAGIC), %g2 + + ldsb [%o0], %g3 +mzero_still_not_word_aligned: + cmp %g3, 0 + bne 1f + add %o0, 1, %o0 + + retl + sub %o0, 1, %o0 + +1: + subcc %o1, 1, %o1 + bne,a 1f + andcc %o0, 3, %g0 + + retl + nop + +1: + bne,a mzero_still_not_word_aligned + ldsb [%o0], %g3 + + sethi %hi(HI_MAGIC), %g2 +mzero_scan_word: + or %g2, %lo(HI_MAGIC), %o3 + sethi %hi(LO_MAGIC), %g3 + or %g3, %lo(LO_MAGIC), %o2 +mzero_next_word: + ld [%o0], %g2 +mzero_next_word_preloaded: + sub %g2, %o2, %g2 +mzero_next_word_preloaded_next: + andcc %g2, %o3, %g0 + bne mzero_byte_zero + add %o0, 4, %o0 + +mzero_check_out_of_fuel: + subcc %o1, 4, %o1 + bg,a 1f + ld [%o0], %g2 + + retl + nop + +1: + b mzero_next_word_preloaded_next + sub %g2, %o2, %g2 + + /* Check every byte. */ +mzero_byte_zero: + ldsb [%o0 - 4], %g2 + cmp %g2, 0 + bne mzero_byte_one + sub %o0, 4, %g3 + + retl + mov %g3, %o0 + +mzero_byte_one: + ldsb [%o0 - 3], %g2 + cmp %g2, 0 + bne,a mzero_byte_two_and_three + ldsb [%o0 - 2], %g2 + + retl + sub %o0, 3, %o0 + +mzero_byte_two_and_three: + cmp %g2, 0 + bne,a 1f + ldsb [%o0 - 1], %g2 + + retl + sub %o0, 2, %o0 + +1: + cmp %g2, 0 + bne,a mzero_next_word_preloaded + ld [%o0], %g2 + + retl + sub %o0, 1, %o0 + +mzero_found_it: + retl + sub %o0, 2, %o0 + +memscan: +__memscan_generic: + /* %o0 = addr, %o1 = c, %o2 = size */ + cmp %o2, 0 + bne,a 0f + ldub [%o0], %g2 + + b,a 2f +1: + ldub [%o0], %g2 +0: + cmp %g2, %o1 + be 2f + addcc %o2, -1, %o2 + bne 1b + add %o0, 1, %o0 +2: + retl + nop |