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Diffstat (limited to 'sysdeps/ia64/fpu/s_nearbyint.S')
| -rw-r--r-- | sysdeps/ia64/fpu/s_nearbyint.S | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/sysdeps/ia64/fpu/s_nearbyint.S b/sysdeps/ia64/fpu/s_nearbyint.S new file mode 100644 index 0000000..ec1ff22 --- /dev/null +++ b/sysdeps/ia64/fpu/s_nearbyint.S @@ -0,0 +1,217 @@ +.file "nearbyint.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 +//============================================================== +// 10/19/00 Created +// 02/08/01 Corrected behavior for all rounding modes. +// 05/20/02 Cleaned up namespace and sf0 syntax +// 02/10/03 Reordered header: .section, .global, .proc, .align +// 07/25/03 Improved performance +//============================================================== + +// API +//============================================================== +// double nearbyint(double x) +//============================================================== + +// general input registers: +// r14 - r21 + +rSignexp = r14 +rExp = r15 +rExpMask = r16 +rBigexp = r17 +rFpsr = r19 +rRcs0 = r20 +rRcs0Mask = r21 + +// floating-point registers: +// f8 - f10 + +fXInt = f9 +fNormX = f10 + +// predicate registers used: +// p6 - p10 + +// Overview of operation +//============================================================== +// double nearbyint(double x) +// Return an integer value (represented as a double) that is x +// rounded to integer in current rounding mode +// Inexact is not set, otherwise result identical with rint. +//============================================================== + +// 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(nearbyint) + +{ .mfi + getf.exp rSignexp = f8 // Get signexp, recompute if unorm + fclass.m p7,p0 = f8, 0x0b // Test x unorm + addl rBigexp = 0x10033, r0 // Set exponent at which is integer +} +{ .mfi + nop.m 0 + fcvt.fx.s1 fXInt = f8 // Convert to int in significand + mov rExpMask = 0x1FFFF // Form exponent mask +} +;; + +{ .mfi + mov rFpsr = ar40 // Read fpsr -- check rc.s0 + fclass.m p6,p0 = f8, 0x1e3 // Test x natval, nan, inf + nop.i 0 +} +{ .mfb + nop.m 0 + fnorm.s1 fNormX = f8 // Normalize input +(p7) br.cond.spnt RINT_UNORM // Branch if x unorm +} +;; + + +RINT_COMMON: +// Return here from RINT_UNORM +{ .mfb + and rExp = rSignexp, rExpMask // Get biased exponent +(p6) fma.d.s0 f8 = f8, f1, f0 // Result if x natval, nan, inf +(p6) br.ret.spnt b0 // Exit if x natval, nan, inf +} +;; + +{ .mfi + mov rRcs0Mask = 0x0c00 // Mask for rc.s0 + fcvt.xf f8 = fXInt // Result assume |x| < 2^52 + cmp.ge p7,p8 = rExp, rBigexp // Is |x| >= 2^52? +} +;; + +// We must correct result if |x| >= 2^52 +{ .mfi + nop.m 0 +(p7) fma.d.s0 f8 = fNormX, f1, f0 // If |x| >= 2^52, result x + nop.i 0 +} +;; + +{ .mfi + nop.m 0 +(p8) fmerge.s f8 = fNormX, f8 // Make sign nearbyint(x) = sign x + nop.i 0 +} +;; + +{ .mfi +(p8) and rRcs0 = rFpsr, rRcs0Mask // Get rounding mode for sf0 + nop.f 0 + nop.i 0 +} +;; + +// If |x| < 2^52 we must test for other rounding modes +{ .mbb +(p8) cmp.ne.unc p10,p0 = rRcs0, r0 // Test for other rounding modes +(p10) br.cond.spnt RINT_NOT_ROUND_NEAREST // Branch if not round nearest + br.ret.sptk b0 // Exit main path if round nearest +} +;; + + +RINT_UNORM: +// Here if x unorm +{ .mfb + getf.exp rSignexp = fNormX // Get signexp, recompute if unorm + fcmp.eq.s0 p7,p0 = f8, f0 // Dummy op to set denormal flag + br.cond.sptk RINT_COMMON // Return to main path +} +;; + +RINT_NOT_ROUND_NEAREST: +// Here if not round to nearest, and |x| < 2^52 +// Set rounding mode of s2 to that of s0, and repeat the conversion using s2 +{ .mfi + nop.m 0 + fsetc.s2 0x7f, 0x40 + nop.i 0 +} +;; + +{ .mfi + nop.m 0 + fcvt.fx.s2 fXInt = fNormX // Convert to int in significand + nop.i 0 +} +;; + +{ .mfi + nop.m 0 + fcvt.xf f8 = fXInt // Expected result + nop.i 0 +} +;; + +// Be sure sign of result = sign of input. Fixes cases where result is 0. +{ .mfb + nop.m 0 + fmerge.s f8 = fNormX, f8 + br.ret.sptk b0 // Exit main path +} +;; + +GLOBAL_LIBM_END(nearbyint) |