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Diffstat (limited to 'sysdeps/ia64/fpu/libm_frexp4.S')
| -rw-r--r-- | sysdeps/ia64/fpu/libm_frexp4.S | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/sysdeps/ia64/fpu/libm_frexp4.S b/sysdeps/ia64/fpu/libm_frexp4.S new file mode 100644 index 0000000000..f20a00b154 --- /dev/null +++ b/sysdeps/ia64/fpu/libm_frexp4.S @@ -0,0 +1,185 @@ +.file "libm_frexp_4.s" + +// Copyright (c) 2000, 2001, Intel Corporation +// All rights reserved. +// +// Contributed 2/2/2000 by John Harrison, 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. +// +// History +//============================================================== +// 2/02/00: Initial version +// 3/20/00: Improved speed +// 6/01/00: Fixed bug when x a double-extended denormal +// 12/08/00 Corrected label on .endp +// +// API +//============================================================== +// double frexp(double x, int* y) +// double __libm_frexp_4(double x, int* y) +// where int* y is a 32-bit integer +// +// Overview of operation +//============================================================== +// break a floating point x number into fraction and an exponent +// The fraction is returned as a double +// The exponent is returned as an integer pointed to by y +// This is a true (not a biased exponent) but 0fffe is subtracted +// as a bias instead of 0xffff. This is because the fraction returned +// is between 0.5 and 1.0, not the expected IEEE range. +// +// The fraction is 0.5 <= fraction < 1.0 +// +// Registers used +//============================================================== +// +// general registers: +// r14 exponent bias for x negative +// r15 exponent bias for x positive +// r16 signexp of x +// r17 exponent mask +// r18 exponent of x +// r19 exponent result +// r20 signexp of 2^64 +// r32 on input contains the 64-bit IEEE double that is in f8 +// r33 on input pointer to 32-bit integer for exponent +// +// predicate registers: +// p6 set if x is Nan, zero, or infinity +// p7 set if x negative +// p8 set if x positive +// p9 set if x double-extended denormal +// +// floating-point registers: +// f8 input, output +// f9 normalized x +// f10 signexp for significand result for x positive +// f11 signexp for significand result for x negative +// f12 2^64 + +#include "libm_support.h" + +.align 32 +.global __libm_frexp_4# + +.section .text +.proc __libm_frexp_4# +.align 32 + +__libm_frexp_4: + +// Set signexp for significand result for x>0 +// If x is a NaN, zero, or infinity, return it. +// Put 0 in the int pointer. +// x NAN, ZERO, INFINITY? +// Set signexp for significand result for x<0 +{ .mfi +(p0) mov r15 = 0x0fffe +(p0) fclass.m.unc p6,p0 = f8, 0xe7 +(p0) mov r14 = 0x2fffe +} +// Form signexp of 2^64 in case x double-extended denormal +// Save the normalized value of input in f9 +// The normalization also sets fault flags and takes faults if necessary +{ .mfi +(p0) mov r20 = 0x1003f +(p0) fnorm f9 = f8 + nop.i 999 ;; +} + +// Move signexp for significand result for x>0 to FP reg +// Form 2^64 in case x double-extended denormal +{ .mmi +(p0) setf.exp f10 = r15 +(p0) setf.exp f12 = r20 + nop.i 999 ;; +} + +// Move signexp for significand result for x<0 to FP reg +// If x NAN, ZERO, INFINITY, set *y=0 as a 32-bit integer, and exit +{ .mmb +(p0) setf.exp f11 = r14 +(p6) st4 [r33] = r0 +(p6) br.ret.spnt b0 ;; +} + +// Form exponent mask +// p7 if x<0, else p8 +{ .mfi +(p0) mov r17 = 0x1ffff +(p0) fcmp.lt.unc p7,p8 = f8,f0 + nop.i 999 ;; +} + +// Test for fnorm(x) denormal, means x double-extended denormal +{ .mfi + nop.m 999 +(p0) fclass.m.unc p9,p0 = f9, 0x0b + nop.i 999 ;; +} + +// If x double-extended denormal add 64 to exponent bias for scaling +// If x double-extended denormal multiply x * 2^64 which is normal +{ .mfi +(p9) add r15 = 64, r15 +(p9) fmpy f9 = f9, f12 + nop.i 999 ;; +} + +// true exponent stored to int pointer +// the bias is treated as 0xfffe instead of +// normal 0xffff because we want the significand +// to be in the range <=0.5 sig < 1.0 +// Store the value of the exponent at the pointer in r33 + +// If x>0 form significand result +{ .mfi + nop.m 999 +(p8) fmerge.se f8 = f10,f9 + nop.i 999 ;; +} + +// Get signexp of normalized x +// If x<0 form significand result +{ .mfi +(p0) getf.exp r16 = f9 +(p7) fmerge.se f8 = f11,f9 + nop.i 999 ;; +} + +// Get exp of normalized x +// Subtract off bias to get true exponent of x +{ .mmi +(p0) and r18 = r17,r16 ;; +(p0) sub r19 = r18,r15 + nop.i 999 ;; +} + +// Store int y as a 32-bit integer +// Make the value a double +{ .mfb +(p0) st4 [r33] = r19 +(p0) fnorm.d f8 = f8 +(p0) br.ret.sptk b0 ;; +} + +.endp __libm_frexp_4 +ASM_SIZE_DIRECTIVE(__libm_frexp_4) |