diff options
Diffstat (limited to 'sysdeps/alpha/ffs.S')
| -rw-r--r-- | sysdeps/alpha/ffs.S | 87 |
1 files changed, 52 insertions, 35 deletions
diff --git a/sysdeps/alpha/ffs.S b/sysdeps/alpha/ffs.S index 6eb3afdff7..91cce4182b 100644 --- a/sysdeps/alpha/ffs.S +++ b/sysdeps/alpha/ffs.S @@ -1,4 +1,4 @@ -/* Copyright (C) 1996, 1997 Free Software Foundation, Inc. +/* Copyright (C) 1996, 1997, 1998 Free Software Foundation, Inc. Contributed by David Mosberger (davidm@cs.arizona.edu). This file is part of the GNU C Library. @@ -25,49 +25,66 @@ .set noreorder .set noat + ENTRY(__ffs) #ifdef PROF ldgp gp, 0(pv) lda AT, _mcount jsr AT, (AT), _mcount .prologue 1 + zap $16, 0xF0, $16 + br $ffsl..ng #else .prologue 0 + zap $16, 0xF0, $16 + # FALLTHRU #endif +END(__ffs) - ldq_u zero, 0(sp) # on the 21064, this helps dual-issuing - addl a0, zero, a0 # the last insn and reduces the stall - negq a0, t0 # due to the srl instruction - and a0, t0, t0 - clr v0 - beq a0, $done - - # now do binary search for first non-zero bit - - zapnot t0, 0x03, t2 - addq v0, 16, t3 - cmoveq t2, t3, v0 - - zapnot t0, 0x05, t2 - addq v0, 8, t3 - cmoveq t2, t3, v0 - - srl t0, v0, t0 - addq v0, 1, v0 - - and t0, 0x0f, t2 - addq v0, 4, t3 - cmoveq t2, t3, v0 - - and t0, 0x33, t2 - addq v0, 2, t3 - cmoveq t2, t3, v0 - - and t0, 0x55, t2 - addq v0, 1, t3 - cmoveq t2, t3, v0 - -$done: ret + .align 4 +ENTRY(ffsl) +#ifdef PROF + ldgp gp, 0(pv) + lda AT, _mcount + jsr AT, (AT), _mcount + .prologue 1 +$ffsl..ng: +#else + .prologue 0 +#endif + not $16, $1 # e0 : + ldi $2, -1 # .. e1 : + cmpbge $1, $2, $3 # e0 : bit N == 1 for byte N == 0 + clr $0 # .. e1 : + addq $3, 1, $4 # e0 : + bic $4, $3, $3 # e1 : bit N == 1 for first byte N != 0 + and $3, 0xF0, $4 # e0 : + and $3, 0xCC, $5 # .. e1 : + and $3, 0xAA, $6 # e0 : + cmovne $4, 4, $0 # .. e1 : + cmovne $5, 2, $5 # e0 : + cmovne $6, 1, $6 # .. e1 : + addl $0, $5, $0 # e0 : + addl $0, $6, $0 # e1 : $0 == N + extbl $16, $0, $1 # e0 : $1 == byte N + ldi $2, 1 # .. e1 : + negq $1, $3 # e0 : + and $3, $1, $3 # e1 : bit N == least bit set of byte N + and $3, 0xF0, $4 # e0 : + and $3, 0xCC, $5 # .. e1 : + and $3, 0xAA, $6 # e0 : + cmovne $4, 5, $2 # .. e1 : + cmovne $5, 2, $5 # e0 : + cmovne $6, 1, $6 # .. e1 : + s8addl $0, $2, $0 # e0 : mult byte ofs by 8 and sum + addl $5, $6, $5 # .. e1 : + addl $0, $5, $0 # e0 : + nop # .. e1 : + cmoveq $16, 0, $0 # e0 : trap input == 0 case. + ret # .. e1 : 18 + +END(ffsl) - END(__ffs) weak_alias (__ffs, ffs) +weak_extern (ffsl) +weak_alias (ffsl, ffsll) |