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Diffstat (limited to 'sysdeps/alpha/w_sqrt.S')
| -rw-r--r-- | sysdeps/alpha/w_sqrt.S | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/sysdeps/alpha/w_sqrt.S b/sysdeps/alpha/w_sqrt.S new file mode 100644 index 0000000000..b5c980e557 --- /dev/null +++ b/sysdeps/alpha/w_sqrt.S @@ -0,0 +1,161 @@ +/* Copyright (C) 1996 Free Software Foundation, Inc. + Contributed by David Mosberger (davidm@cs.arizona.edu). + Based on public-domain C source by Linus Torvalds. + + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public License as + published by the Free Software Foundation; either version 2 of the + License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If + not, write to the Free Software Foundation, Inc., 675 Mass Ave, + Cambridge, MA 02139, USA. */ + +/* This version is much faster than generic sqrt implementation, but + it doesn't handle exceptional values or the inexact flag. Don't use + this if _IEEE_FP or _IEEE_FP_INEXACT is in effect. */ + +#ifndef _IEEE_FP + +#include <errnos.h> +#include <sysdep.h> + + .set noreorder + +#ifdef __ELF__ + .section .rodata +#else + .rdata +#endif + .align 5 # align to cache line + + /* Do all memory accesses relative to sqrtdata. */ +sqrtdata: + +#define DN 0x00 +#define UP 0x08 +#define HALF 0x10 +#define ALMOST_THREE_HALF 0x18 +#define T2 0x20 + + .quad 0x3fefffffffffffff /* DN = next(1.0) */ + .quad 0x3ff0000000000001 /* UP = prev(1.0) */ + .quad 0x3fe0000000000000 /* HALF = 0.5 */ + .quad 0x3ff7ffffffc00000 /* ALMOST_THREE_HALF = 1.5-2^-30 */ + +/* table T2: */ +.long 0x1500, 0x2ef8, 0x4d67, 0x6b02, 0x87be, 0xa395, 0xbe7a, 0xd866 +.long 0xf14a, 0x1091b, 0x11fcd, 0x13552, 0x14999, 0x15c98, 0x16e34, 0x17e5f +.long 0x18d03, 0x19a01, 0x1a545, 0x1ae8a, 0x1b5c4, 0x1bb01, 0x1bfde, 0x1c28d +.long 0x1c2de, 0x1c0db, 0x1ba73, 0x1b11c, 0x1a4b5, 0x1953d, 0x18266, 0x16be0 +.long 0x1683e, 0x179d8, 0x18a4d, 0x19992, 0x1a789, 0x1b445, 0x1bf61, 0x1c989 +.long 0x1d16d, 0x1d77b, 0x1dddf, 0x1e2ad, 0x1e5bf, 0x1e6e8, 0x1e654, 0x1e3cd +.long 0x1df2a, 0x1d635, 0x1cb16, 0x1be2c, 0x1ae4e, 0x19bde, 0x1868e, 0x16e2e +.long 0x1527f, 0x1334a, 0x11051, 0xe951, 0xbe01, 0x8e0d, 0x5924, 0x1edd + +/* + * Stack variables: + */ +#define K 16(sp) +#define Y 24(sp) +#define FSIZE 32 + + .text + +LEAF(__sqrt, FSIZE) + lda sp, -FSIZE(sp) + ldgp gp, .-__sqrt(pv) + stq ra, 0(sp) +#ifdef PROF + lda AT, _mcount + jsr AT, (AT), _mcount +#endif + .prologue 1 + + stt $f16, K + lda t3, sqrtdata # load base address into t3 + + fblt $f16, $negative + + /* Compute initial guess. */ + + .align 3 + + ldah t1, 0x5fe8 # e0 : + ldq t2, K # .. e1 : + ldt $f12, HALF(t3) # e0 : + ldt $f18, ALMOST_THREE_HALF(t3) # .. e1 : + srl t2, 33, t0 # e0 : + mult $f16, $f12, $f11 # .. fm : $f11 = x * 0.5 + subl t1, t0, t1 # e0 : + addt $f12, $f12, $f17 # .. fa : $f17 = 1.0 + srl t1, 12, t0 # e0 : + and t0, 0xfc, t0 # .. e1 : + addq t0, t3, t0 # e0 : + ldl t0, T2(t0) # .. e1 : + addt $f12, $f17, $f15 # fa : $f15 = 1.5 + subl t1, t0, t1 # .. e1 : + sll t1, 32, t1 # e0 : + ldt $f14, DN(t3) # .. e1 : + stq t1, Y # e0 : + ldt $f13, Y # e1 : + addq sp, FSIZE, sp # e0 : + + mult $f11, $f13, $f10 # fm : $f10 = (x * 0.5) * y + mult $f10, $f13, $f10 # fm : $f10 = ((x * 0.5) * y) * y + subt $f15, $f10, $f1 # fa : $f1 = (1.5 - 0.5*x*y*y) + mult $f13, $f1, $f13 # fm : yp = y*(1.5 - 0.5*x*y*y) + mult $f11, $f13, $f11 # fm : $f11 = x * 0.5 * yp + mult $f11, $f13, $f11 # fm : $f11 = (x * 0.5 * yp) * yp + subt $f18, $f11, $f1 # fa : $f1= (1.5-2^-30) - 0.5*x*yp*yp + mult $f13, $f1, $f13 # fm : ypp = $f13 = yp*$f1 + subt $f15, $f12, $f1 # fa : $f1 = (1.5 - 0.5) + ldt $f15, UP(t3) # .. e1 : + mult $f16, $f13, $f10 # fm : z = $f10 = x * ypp + mult $f10, $f13, $f11 # fm : $f11 = z*ypp + mult $f10, $f12, $f12 # fm : $f12 = z*0.5 + subt $f1, $f11, $f1 # .. fa : $f1 = 1 - z*ypp + mult $f12, $f1, $f12 # fm : $f12 = z*0.5*(1 - z*ypp) + addt $f10, $f12, $f0 # fa : zp=res=$f0= z + z*0.5*(1 - z*ypp) + + mult/c $f0, $f14, $f12 # fm : zmi = zp * DN + mult/c $f0, $f15, $f11 # fm : zpl = zp * UP + mult/c $f0, $f12, $f1 # fm : $f1 = zp * zmi + mult/c $f0, $f11, $f15 # fm : $f15 = zp * zpl + + subt $f1, $f16, $f13 # fa : y1 = zp*zmi - x + subt $f15, $f16, $f15 # fa : y2 = zp*zpl - x + + fcmovge $f13, $f12, $f0 # res = (y1 >= 0) ? zmi : res + fcmovlt $f15, $f11, $f0 # res = (y2 < 0) ? zpl : res + + ret + +$negative: + lda t1, -1 + stq t1, K + lda t1, EDOM + stl t1, errno +#ifdef _LIBC_REENTRANT + jsr ra, __errno_location + lda t1, -1 + ldq ra, 0(sp) + stl t1, 0(v0) +#endif + ldt $f0, K # res = (double) 0xffffffffffffffff + addq sp, FSIZE, sp + ret + + END(__sqrt) + +weak_alias(__sqrt, sqrt) + +#endif /* !_IEEE_FP */ |