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Diffstat (limited to 'sysdeps/ia64/fpu/s_nexttoward.S')
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1 files changed, 488 insertions, 0 deletions
diff --git a/sysdeps/ia64/fpu/s_nexttoward.S b/sysdeps/ia64/fpu/s_nexttoward.S new file mode 100644 index 0000000000..f8fac1e072 --- /dev/null +++ b/sysdeps/ia64/fpu/s_nexttoward.S @@ -0,0 +1,488 @@ +.file "nexttoward.s" + + +// Copyright (c) 2001 - 2003, Intel Corporation +// All rights reserved. +// +// Contributed 2001 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 +//============================================================== +// 08/15/01 Initial version +// 08/23/01 Corrected error tag number +// 05/20/02 Cleaned up namespace and sf0 syntax +// 02/10/03 Reordered header: .section, .global, .proc, .align +// +// API +//============================================================== +// double nexttoward( double x, long double y ); +// input floating point f8, f9 +// output floating point f8 +// +// Registers used +//============================================================== +nexttoward_GR_max_pexp = r14 +nexttoward_GR_min_pexp = r15 +nexttoward_GR_exp = r16 +nexttoward_GR_sig = r17 +nexttoward_GR_lnorm_sig = r18 +nexttoward_GR_sign_mask = r19 +nexttoward_GR_exp_mask = r20 +nexttoward_GR_sden_sig = r21 +nexttoward_GR_new_sig = r22 +nexttoward_GR_new_exp = r23 +nexttoward_GR_lden_sig = r24 +nexttoward_GR_snorm_sig = r25 +nexttoward_GR_exp1 = r26 +nexttoward_GR_x_exp = r27 +nexttoward_GR_min_den_rexp = r28 +// r36-39 parameters for libm_error_support + +GR_SAVE_B0 = r34 +GR_SAVE_GP = r35 +GR_SAVE_PFS = r32 + +GR_Parameter_X = r36 +GR_Parameter_Y = r37 +GR_Parameter_RESULT = r38 + +NEXTTOWARD_lnorm_sig = f10 +NEXTTOWARD_lnorm_exp = f11 +NEXTTOWARD_lnorm = f12 +NEXTTOWARD_sden_sig = f13 +NEXTTOWARD_sden_exp = f14 +NEXTTOWARD_sden = f15 +NEXTTOWARD_save_f8 = f33 +NEXTTOWARD_new_exp = f34 +NEXTTOWARD_new_sig = f35 +NEXTTOWARD_lden_sig = f36 +NEXTTOWARD_snorm_sig = f37 +NEXTTOWARD_exp1 = f38 +NEXTTOWARD_tmp = f39 + +// +// Overview of operation +//============================================================== +// nexttoward determines the next representable value +// after x in the direction of y. + + +.section .text +GLOBAL_LIBM_ENTRY(nexttoward) + +// Extract signexp from x +// Is x < y ? p10 if yes, p11 if no +// Form smallest denormal significand = ulp size +{ .mfi + getf.exp nexttoward_GR_exp = f8 + fcmp.lt.s1 p10,p11 = f8, f9 + addl nexttoward_GR_sden_sig = 0x800, r0 +} +// Form largest normal significand 0xfffffffffffff800 +// Form smallest normal exponent +{ .mfi + addl nexttoward_GR_lnorm_sig = -0x800,r0 + nop.f 999 + addl nexttoward_GR_min_pexp = 0x0fc01, r0 ;; +} +// Extract significand from x +// Is x=y? +// Form largest normal exponent +{ .mfi + getf.sig nexttoward_GR_sig = f8 + fcmp.eq.s0 p6,p0 = f8, f9 + addl nexttoward_GR_max_pexp = 0x103fe, r0 +} +// Move largest normal significand to fp reg for special cases +{ .mfi + setf.sig NEXTTOWARD_lnorm_sig = nexttoward_GR_lnorm_sig + nop.f 999 + addl nexttoward_GR_sign_mask = 0x20000, r0 ;; +} + +// Move smallest denormal significand and signexp to fp regs +// Is x=nan? +// Set p12 and p13 based on whether significand increases or decreases +// It increases (p12 set) if x<y and x>=0 or if x>y and x<0 +// It decreases (p13 set) if x<y and x<0 or if x>y and x>=0 +{ .mfi + setf.sig NEXTTOWARD_sden_sig = nexttoward_GR_sden_sig + fclass.m p8,p0 = f8, 0xc3 +(p10) cmp.lt p12,p13 = nexttoward_GR_exp, nexttoward_GR_sign_mask +} +{ .mfi + setf.exp NEXTTOWARD_sden_exp = nexttoward_GR_min_pexp +(p11) cmp.ge p12,p13 = nexttoward_GR_exp, nexttoward_GR_sign_mask ;; +} + +.pred.rel "mutex",p12,p13 + +// Form expected new significand, adding or subtracting 1 ulp increment +// If x=y set result to y +// Form smallest normal significand and largest denormal significand +{ .mfi +(p12) add nexttoward_GR_new_sig = nexttoward_GR_sig, nexttoward_GR_sden_sig +(p6) fnorm.d.s0 f8=f9 //Normalise + dep.z nexttoward_GR_snorm_sig = 1,63,1 // 0x8000000000000000 +} +{ .mlx +(p13) sub nexttoward_GR_new_sig = nexttoward_GR_sig, nexttoward_GR_sden_sig + movl nexttoward_GR_lden_sig = 0x7ffffffffffff800 ;; +} + +// Move expected result significand and signexp to fp regs +// Is y=nan? +// Form new exponent in case result exponent needs incrementing or decrementing +{ .mfi + setf.exp NEXTTOWARD_new_exp = nexttoward_GR_exp + fclass.m p9,p0 = f9, 0xc3 +(p12) add nexttoward_GR_exp1 = 1, nexttoward_GR_exp +} +{ .mib + setf.sig NEXTTOWARD_new_sig = nexttoward_GR_new_sig +(p13) add nexttoward_GR_exp1 = -1, nexttoward_GR_exp +(p6) br.ret.spnt b0 ;; // Exit if x=y +} + +// Move largest normal signexp to fp reg for special cases +// Is x=zero? +{ .mfi + setf.exp NEXTTOWARD_lnorm_exp = nexttoward_GR_max_pexp + fclass.m p7,p0 = f8, 0x7 + nop.i 999 +} +{ .mfb + nop.m 999 +(p8) fma.s0 f8 = f8,f1,f9 +(p8) br.ret.spnt b0 ;; // Exit if x=nan +} + +// Move exp+-1 and smallest normal significand to fp regs for special cases +// Is x=inf? +{ .mfi + setf.exp NEXTTOWARD_exp1 = nexttoward_GR_exp1 + fclass.m p6,p0 = f8, 0x23 + addl nexttoward_GR_exp_mask = 0x1ffff, r0 +} +{ .mfb + setf.sig NEXTTOWARD_snorm_sig = nexttoward_GR_snorm_sig +(p9) fma.s0 f8 = f8,f1,f9 +(p9) br.ret.spnt b0 ;; // Exit if y=nan +} + +// Move largest denormal significand to fp regs for special cases +// Save x +{ .mfb + setf.sig NEXTTOWARD_lden_sig = nexttoward_GR_lden_sig + mov NEXTTOWARD_save_f8 = f8 +(p7) br.cond.spnt NEXTTOWARD_ZERO ;; // Exit if x=0 +} + +// Mask off the sign to get x_exp +{ .mfb + and nexttoward_GR_x_exp = nexttoward_GR_exp_mask, nexttoward_GR_exp + nop.f 999 +(p6) br.cond.spnt NEXTTOWARD_INF ;; // Exit if x=inf +} + +// Check 6 special cases when significand rolls over: +// 1 sig size incr, x_sig=max_sig, x_exp < max_exp +// Set p6, result is sig=min_sig, exp++ +// 2 sig size incr, x_sig=max_sig, x_exp >= max_exp +// Set p7, result is inf, signal overflow +// 3 sig size decr, x_sig=min_sig, x_exp > min_exp +// Set p8, result is sig=max_sig, exp-- +// 4 sig size decr, x_sig=min_sig, x_exp = min_exp +// Set p9, result is sig=max_den_sig, exp same, signal underflow and inexact +// 5 sig size decr, x_sig=min_den_sig, x_exp = min_exp +// Set p10, result is zero, sign of x, signal underflow and inexact +// 6 sig size decr, x_sig=min_sig, x_exp < min_exp +// Set p14, result is zero, sign of x, signal underflow and inexact +// +// Form exponent of smallest double denormal (if normalized register format) +{ .mmi + adds nexttoward_GR_min_den_rexp = -52, nexttoward_GR_min_pexp +(p12) cmp.eq.unc p6,p0 = nexttoward_GR_new_sig, r0 +(p13) cmp.eq.unc p8,p10 = nexttoward_GR_new_sig, nexttoward_GR_lden_sig ;; +} + +{ .mmi +(p6) cmp.lt.unc p6,p7 = nexttoward_GR_x_exp, nexttoward_GR_max_pexp +(p8) cmp.gt.unc p8,p9 = nexttoward_GR_x_exp, nexttoward_GR_min_pexp +(p10) cmp.eq.unc p10,p0 = nexttoward_GR_new_sig, r0 ;; +} + +// Create small normal in case need to generate underflow flag +{ .mfi +(p10) cmp.le.unc p10,p0 = nexttoward_GR_x_exp, nexttoward_GR_min_pexp + fmerge.se NEXTTOWARD_tmp = NEXTTOWARD_sden_exp, NEXTTOWARD_lnorm_sig +(p9) cmp.gt.unc p9,p14 = nexttoward_GR_x_exp, nexttoward_GR_min_den_rexp +} +// Branch if cases 1, 2, 3 +{ .bbb +(p6) br.cond.spnt NEXTTOWARD_EXPUP +(p7) br.cond.spnt NEXTTOWARD_OVERFLOW +(p8) br.cond.spnt NEXTTOWARD_EXPDOWN ;; +} + +// Branch if cases 4, 5, 6 +{ .bbb +(p9) br.cond.spnt NEXTTOWARD_NORM_TO_DENORM +(p10) br.cond.spnt NEXTTOWARD_UNDERFLOW_TO_ZERO +(p14) br.cond.spnt NEXTTOWARD_UNDERFLOW_TO_ZERO ;; +} + +// Here if no special cases +// Set p6 if result will be a denormal, so can force underflow flag +// Case 1: x_exp=min_exp, x_sig=unnormalized +// Case 2: x_exp<min_exp +{ .mfi + cmp.lt p6,p7 = nexttoward_GR_x_exp, nexttoward_GR_min_pexp + fmerge.se f8 = NEXTTOWARD_new_exp, NEXTTOWARD_new_sig + nop.i 999 ;; +} + +{ .mfi + nop.m 999 + nop.f 999 +(p7) tbit.z p6,p0 = nexttoward_GR_new_sig, 63 ;; +} + +NEXTTOWARD_COMMON_FINISH: +// Force underflow and inexact if denormal result +{ .mfi + nop.m 999 +(p6) fma.d.s0 NEXTTOWARD_tmp = NEXTTOWARD_tmp,NEXTTOWARD_tmp,f0 + nop.i 999 ;; +} + +// Final normalization to result precision and exit +{ .mfb + nop.m 999 + fnorm.d.s0 f8 = f8 + br.ret.sptk b0;; +} + +//Special cases +NEXTTOWARD_EXPUP: +{ .mfb + cmp.lt p6,p7 = nexttoward_GR_x_exp, nexttoward_GR_min_pexp + fmerge.se f8 = NEXTTOWARD_exp1, NEXTTOWARD_snorm_sig + br.cond.sptk NEXTTOWARD_COMMON_FINISH ;; +} + +NEXTTOWARD_EXPDOWN: +{ .mfb + cmp.lt p6,p7 = nexttoward_GR_x_exp, nexttoward_GR_min_pexp + fmerge.se f8 = NEXTTOWARD_exp1, NEXTTOWARD_lnorm_sig + br.cond.sptk NEXTTOWARD_COMMON_FINISH ;; +} + +NEXTTOWARD_NORM_TO_DENORM: +{ .mfi + nop.m 999 + fmerge.se f8 = NEXTTOWARD_new_exp, NEXTTOWARD_lden_sig + nop.i 999 +} +// Force underflow and inexact if denormal result +{ .mfb + nop.m 999 + fma.d.s0 NEXTTOWARD_tmp = NEXTTOWARD_tmp,NEXTTOWARD_tmp,f0 + br.ret.sptk b0 ;; +} + +NEXTTOWARD_UNDERFLOW_TO_ZERO: +{ .mfb + cmp.eq p6,p0 = r0,r0 + fmerge.s f8 = NEXTTOWARD_save_f8,f0 + br.cond.sptk NEXTTOWARD_COMMON_FINISH ;; +} + +NEXTTOWARD_INF: +// Here if f8 is +- infinity +// INF +// if f8 is +inf, no matter what y is return largest double +// if f8 is -inf, no matter what y is return -largest double + +{ .mfi + nop.m 999 + fmerge.se NEXTTOWARD_lnorm = NEXTTOWARD_lnorm_exp,NEXTTOWARD_lnorm_sig + nop.i 999 ;; +} + +{ .mfb + nop.m 999 + fmerge.s f8 = f8,NEXTTOWARD_lnorm + br.ret.sptk b0 ;; +} + +NEXTTOWARD_ZERO: + +// Here if f8 is +- zero +// ZERO +// if f8 is zero and y is +, return + smallest double denormal +// if f8 is zero and y is -, return - smallest double denormal + +{ .mfi + nop.m 999 + fmerge.se NEXTTOWARD_sden = NEXTTOWARD_sden_exp,NEXTTOWARD_sden_sig + nop.i 999 ;; +} + +// Create small normal to generate underflow flag +{ .mfi + nop.m 999 + fmerge.se NEXTTOWARD_tmp = NEXTTOWARD_sden_exp, NEXTTOWARD_lnorm_sig + nop.i 999 ;; +} + +// Add correct sign from direction arg +{ .mfi + nop.m 999 + fmerge.s f8 = f9,NEXTTOWARD_sden + nop.i 999 ;; +} + +// Force underflow and inexact flags +{ .mfb + nop.m 999 + fma.d.s0 NEXTTOWARD_tmp = NEXTTOWARD_tmp,NEXTTOWARD_tmp,f0 + br.ret.sptk b0 ;; +} + +GLOBAL_LIBM_END(nexttoward) +// Stack operations when calling error support. +// (1) (2) (3) (call) (4) +// sp -> + psp -> + psp -> + sp -> + +// | | | | +// | | <- GR_Y R3 ->| <- GR_RESULT | -> f8 +// | | | | +// | <-GR_Y Y2->| Y2 ->| <- GR_Y | +// | | | | +// | | <- GR_X X1 ->| | +// | | | | +// sp-64 -> + sp -> + sp -> + + +// save ar.pfs save b0 restore gp +// save gp restore ar.pfs + + + +LOCAL_LIBM_ENTRY(__libm_error_region) +NEXTTOWARD_OVERFLOW: +// Here if f8 is finite, but result will be infinite +// Use frcpa to generate infinity of correct sign +// Call error support to report possible range error +.prologue + +{ .mfi + alloc r32=ar.pfs,2,2,4,0 + frcpa.s1 f8,p6 = NEXTTOWARD_save_f8, f0 + nop.i 999 ;; +} + +// Create largest double +{ .mfi + nop.m 999 + fmerge.se NEXTTOWARD_lnorm = NEXTTOWARD_lnorm_exp,NEXTTOWARD_lnorm_sig + nop.i 999 ;; +} + +// Force overflow and inexact flags to be set +{ .mfi + mov r39 = 199 // Error code + fma.d.s0 NEXTTOWARD_tmp = NEXTTOWARD_lnorm,NEXTTOWARD_lnorm,f0 + nop.i 999 +} +;; + +// (1) +{ .mfi + add GR_Parameter_Y=-32,sp // Parameter 2 value + nop.f 0 +.save ar.pfs,GR_SAVE_PFS + mov GR_SAVE_PFS=ar.pfs // Save ar.pfs +} +{ .mfi +.fframe 64 + add sp=-64,sp // Create new stack + nop.f 0 + mov GR_SAVE_GP=gp // Save gp +};; + + +// (2) +{ .mmi + stfd [GR_Parameter_Y] = f9,16 // STORE Parameter 2 on stack + add GR_Parameter_X = 16,sp // Parameter 1 address +.save b0, GR_SAVE_B0 + mov GR_SAVE_B0=b0 // Save b0 +};; + +.body +// (3) +{ .mib + stfd [GR_Parameter_X] = NEXTTOWARD_save_f8 // STORE Parameter 1 on stack + add GR_Parameter_RESULT = 0,GR_Parameter_Y // Parameter 3 address + nop.b 0 +} +{ .mib + stfd [GR_Parameter_Y] = f8 // STORE Parameter 3 on stack + add GR_Parameter_Y = -16,GR_Parameter_Y + br.call.sptk b0=__libm_error_support# // Call error handling function +};; +{ .mmi + nop.m 0 + nop.m 0 + add GR_Parameter_RESULT = 48,sp +};; + +// (4) +{ .mmi + ldfd f8 = [GR_Parameter_RESULT] // Get return result off stack +.restore sp + add sp = 64,sp // Restore stack pointer + mov b0 = GR_SAVE_B0 // Restore return address +};; +{ .mib + mov gp = GR_SAVE_GP // Restore gp + mov ar.pfs = GR_SAVE_PFS // Restore ar.pfs + br.ret.sptk b0 // Return +};; + +LOCAL_LIBM_END(__libm_error_region) + + +.type __libm_error_support#,@function +.global __libm_error_support# + |