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Diffstat (limited to 'sysdeps/ia64/fpu/s_trunc.S')
| -rw-r--r-- | sysdeps/ia64/fpu/s_trunc.S | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/sysdeps/ia64/fpu/s_trunc.S b/sysdeps/ia64/fpu/s_trunc.S new file mode 100644 index 0000000000..976ddf1517 --- /dev/null +++ b/sysdeps/ia64/fpu/s_trunc.S @@ -0,0 +1,188 @@ +.file "trunc.s" + +// Copyright (c) 2000, 2001, Intel Corporation +// All rights reserved. +// +// Contributed 7/7/2000 by John Harrison, Cristina Iordache, Ted Kubaska, +// Bob Norin, Shane Story, and Ping Tak Peter Tang of the +// Computational Software Lab, Intel Corporation. +// +// WARRANTY DISCLAIMER +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL INTEL OR ITS +// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, +// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, +// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR +// PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY +// OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY OR TORT (INCLUDING +// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS +// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +// +// Intel Corporation is the author of this code, and requests that all +// problem reports or change requests be submitted to it directly at +// http://developer.intel.com/opensource. +// +.align 32 +.global trunc# + +.section .text +.proc trunc# +.align 32 + +// History +//============================================================== +// 7/7/00: Created +//============================================================== + +// API +//============================================================== +// double trunc(double x) +//============================================================== + +#include "libm_support.h" + +// general input registers: +TRUNC_GR_FFFF = r14 +TRUNC_GR_signexp = r15 +TRUNC_GR_exponent = r16 +TRUNC_GR_expmask = r17 +TRUNC_GR_bigexp = r18 + +// floating-point registers: +// f8, f9, f11, f12 + +// predicate registers used: +// p6, p7, p8, p9, p10, p11 + +// Overview of operation +//============================================================== +// double trunc(double x) +// Return an integer value (represented as a double) less than or +// equal to x in magnitude. +// This is x rounded toward zero to an integral value. +//============================================================== + +// double_extended +// if the exponent is > 1003e => 3F(true) = 63(decimal) +// we have a significand of 64 bits 1.63-bits. +// If we multiply by 2^63, we no longer have a fractional part +// So input is an integer value already. + +// double +// if the exponent is >= 10033 => 34(true) = 52(decimal) +// 34 + 3ff = 433 +// we have a significand of 53 bits 1.52-bits. (implicit 1) +// If we multiply by 2^52, we no longer have a fractional part +// So input is an integer value already. + +// single +// if the exponent is > 10016 => 17(true) = 23(decimal) +// we have a significand of 24 bits 1.23-bits. (implicit 1) +// If we multiply by 2^23, we no longer have a fractional part +// So input is an integer value already. + +trunc: + +{ .mfi + getf.exp TRUNC_GR_signexp = f8 + fcvt.fx.trunc.s1 f9 = f8 + addl TRUNC_GR_bigexp = 0x10033, r0 +} +{ .mfi + mov TRUNC_GR_FFFF = 0x0FFFF + fnorm.d f11 = f8 + mov TRUNC_GR_expmask = 0x1FFFF +};; +// get the exponent of x +// convert x to integer in signficand of f9 +// Normalize x - this will raise invalid on SNaNs, the +// denormal operand flag - and possibly a spurious U flag +// get exponent only mask (will exclude sign bit) + +{ .mfi + nop.m 0 + fclass.m p7,p8 = f8, 0x0b + nop.i 0 +} +{ .mfi + nop.m 0 + fcmp.eq.unc.s1 p9,p0 = f8,f0 + nop.i 0 +};; +// fclass to set p7 if unnorm +{ .mmi + and TRUNC_GR_exponent = TRUNC_GR_signexp, TRUNC_GR_expmask ;; +(p8) cmp.ge.unc p10,p11 = TRUNC_GR_exponent, TRUNC_GR_bigexp +(p8) cmp.ne.unc p6,p0 = TRUNC_GR_exponent, TRUNC_GR_signexp +};; +// Get the exponent of x +// Test if exponent such that result already an integer +// Test if x < 0 +{ .mmi +(p9) cmp.eq.andcm p10,p11 = r0, r0 +(p6) cmp.lt.unc p6,p0 = TRUNC_GR_exponent, TRUNC_GR_FFFF + nop.i 0 +};; +// If -1 < x < 0, set p6, turn off p10 and p11, and set result to -0.0 +{ .mfb +(p6) cmp.eq.andcm p10,p11 = r0, r0 +(p6) fmerge.s f8 = f8, f0 + nop.b 0 +};; +// If not a unnorm, set p10 if x already is a big int, nan, or inf? +// If not a unnorm, set p10 if x already is a big int, nan, or inf? +.pred.rel "mutex",p10,p11 +{ .mfb + nop.m 0 +(p11) fcvt.xf f8 = f9 + nop.b 0 +} +{ .mfb + nop.m 0 +(p10) fma.d.s1 f8 = f11,f1,f0 +(p8) br.ret.sptk b0 +};; +// If not a unnorm and not an big int, nan,or +/-inf convert signficand +// back to f8. +// If not a unorm and a big int, nan, or +/-inf, return fnorm'd x +// If not a unorm, Return +// If unnorm, get the exponent again - perhaps it wasn't a denorm. +{ .mfb +(p7) getf.exp TRUNC_GR_signexp = f11 +(p7) fcvt.fx.trunc.s1 f12 = f11 + nop.b 0 +};; +{ .mfb + and TRUNC_GR_exponent = TRUNC_GR_signexp, TRUNC_GR_expmask + fcmp.lt.unc.s1 p9,p0 = f8,f0 + nop.b 0 +};; +{ .mfb + cmp.ge.unc p10,p11 = TRUNC_GR_exponent, TRUNC_GR_bigexp + nop.f 0 + nop.b 0 +};; +// If a unnorm, check to see if value is already a big int. +{ .mfb + nop.m 0 +(p11) fcvt.xf f8 = f12 + nop.b 0 +} +{ .mfi + nop.m 0 +(p10) fma.d.s1 f8 = f11,f1,f0 + nop.i 0 +};; +{ .mfb + nop.m 0 +(p9) fmerge.ns f8 = f1,f8 + br.ret.sptk b0 +};; +// If so return it. Otherwise, return (fcvt.xf(fcvt.fx.trunc(x))) +// Make sure the result is negative if it should be - that is +// negative(denormal) -> -0. +.endp trunc +ASM_SIZE_DIRECTIVE(trunc) |