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Diffstat (limited to 'ports/sysdeps/ia64/fpu/s_round.S')
| -rw-r--r-- | ports/sysdeps/ia64/fpu/s_round.S | 233 |
1 files changed, 233 insertions, 0 deletions
diff --git a/ports/sysdeps/ia64/fpu/s_round.S b/ports/sysdeps/ia64/fpu/s_round.S new file mode 100644 index 0000000000..821187522b --- /dev/null +++ b/ports/sysdeps/ia64/fpu/s_round.S @@ -0,0 +1,233 @@ +.file "round.s" + + +// Copyright (c) 2000 - 2003, Intel Corporation +// All rights reserved. +// +// Contributed 2000 by the Intel Numerics Group, Intel Corporation +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// +// * Redistributions in binary form must reproduce the above copyright +// notice, this list of conditions and the following disclaimer in the +// documentation and/or other materials provided with the distribution. +// +// * The name of Intel Corporation may not be used to endorse or promote +// products derived from this software without specific prior written +// permission. + +// 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://www.intel.com/software/products/opensource/libraries/num.htm. +// +// History +//============================================================== +// 10/25/00 Initial version +// 06/14/01 Changed cmp to an equivalent form +// 05/20/02 Cleaned up namespace and sf0 syntax +// 01/20/03 Improved performance and reduced code size +// 04/18/03 Eliminate possible WAW dependency warning +// 09/03/03 Improved performance +//============================================================== + +// API +//============================================================== +// double round(double x) +//============================================================== + +// general input registers: +// r14 - r18 + +rSignexp = r14 +rExp = r15 +rExpMask = r16 +rBigexp = r17 +rExpHalf = r18 + +// floating-point registers: +// f8 - f13 + +fXtruncInt = f9 +fNormX = f10 +fHalf = f11 +fInc = f12 +fRem = f13 + +// predicate registers used: +// p6 - p10 + +// Overview of operation +//============================================================== +// double round(double x) +// Return an integer value (represented as a double) that is x +// rounded to nearest integer, halfway cases rounded away from +// zero. +// if x>0 result = trunc(x+0.5) +// if x<0 result = trunc(x-0.5) +// +//============================================================== + +// 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. + + +.section .text +GLOBAL_LIBM_ENTRY(round) + +{ .mfi + getf.exp rSignexp = f8 // Get signexp, recompute if unorm + fcvt.fx.trunc.s1 fXtruncInt = f8 // Convert to int in significand + addl rBigexp = 0x10033, r0 // Set exponent at which is integer +} +{ .mfi + mov rExpHalf = 0x0FFFE // Form sign and exponent of 0.5 + fnorm.s1 fNormX = f8 // Normalize input + mov rExpMask = 0x1FFFF // Form exponent mask +} +;; + +{ .mfi + setf.exp fHalf = rExpHalf // Form 0.5 + fclass.m p7,p0 = f8, 0x0b // Test x unorm + nop.i 0 +} +;; + +{ .mfb + nop.m 0 + fclass.m p6,p0 = f8, 0x1e3 // Test x natval, nan, inf +(p7) br.cond.spnt ROUND_UNORM // Branch if x unorm +} +;; + +ROUND_COMMON: +// Return here from ROUND_UNORM +{ .mfb + nop.m 0 + fcmp.lt.s1 p8,p9 = f8, f0 // Test if x < 0 +(p6) br.cond.spnt ROUND_SPECIAL // Exit if x natval, nan, inf +} +;; + +{ .mfi + nop.m 0 + fcvt.xf f8 = fXtruncInt // Pre-Result if 0.5 <= |x| < 2^52 + nop.i 0 +} +;; + +{ .mfi + and rExp = rSignexp, rExpMask // Get biased exponent + fmerge.s fInc = fNormX, f1 // Form increment if |rem| >= 0.5 + nop.i 0 +} +;; + +{ .mmi + cmp.lt p6,p0 = rExp, rExpHalf // Is |x| < 0.5? + cmp.ge p7,p0 = rExp, rBigexp // Is |x| >= 2^52? + cmp.lt p10,p0 = rExp, rExpHalf // Is |x| < 0.5? +} +;; + +// We must correct result if |x| < 0.5, or |x| >= 2^52 +.pred.rel "mutex",p6,p7 +{ .mfi + nop.m 0 +(p6) fmerge.s f8 = fNormX, f0 // If |x| < 0.5, result sgn(x)*0 + nop.i 0 +} +{ .mfb +(p7) cmp.eq p10,p0 = r0, r0 // Also turn on p10 if |x| >= 2^52 +(p7) fma.d.s0 f8 = fNormX, f1, f0 // If |x| >= 2^52, result x +(p10) br.ret.spnt b0 // Exit |x| < 0.5 or |x| >= 2^52 +} +;; + +// Here if 0.5 <= |x| < 2^52 +{ .mfi + nop.m 0 +(p9) fms.s1 fRem = fNormX, f1, f8 // Get remainder = x - trunc(x) + nop.i 0 +} +{ .mfi + nop.m 0 +(p8) fms.s1 fRem = f8, f1, fNormX // Get remainder = trunc(x) - x + nop.i 0 +} +;; + +{ .mfi + nop.m 0 + fcmp.ge.s1 p9,p0 = fRem, fHalf // Test |rem| >= 0.5 + nop.i 0 +} +;; + +// If x < 0 and remainder <= -0.5, then subtract 1 from result +// If x > 0 and remainder >= +0.5, then add 1 to result +{ .mfb + nop.m 0 +(p9) fma.d.s0 f8 = f8, f1, fInc + br.ret.sptk b0 +} +;; + + +ROUND_SPECIAL: +// Here if x natval, nan, inf +{ .mfb + nop.m 0 + fma.d.s0 f8 = f8, f1, f0 + br.ret.sptk b0 +} +;; + +ROUND_UNORM: +// Here if x unorm +{ .mfi + getf.exp rSignexp = fNormX // Get signexp, recompute if unorm + fcmp.eq.s0 p7,p0 = f8, f0 // Dummy op to set denormal flag + nop.i 0 +} +{ .mfb + nop.m 0 + fcvt.fx.trunc.s1 fXtruncInt = fNormX // Convert to int in significand + br.cond.sptk ROUND_COMMON // Return to main path +} +;; + +GLOBAL_LIBM_END(round) |