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Diffstat (limited to 'sysdeps/ia64/fpu/s_logb.S')
| -rw-r--r-- | sysdeps/ia64/fpu/s_logb.S | 281 |
1 files changed, 281 insertions, 0 deletions
diff --git a/sysdeps/ia64/fpu/s_logb.S b/sysdeps/ia64/fpu/s_logb.S new file mode 100644 index 0000000..7ee8987 --- /dev/null +++ b/sysdeps/ia64/fpu/s_logb.S @@ -0,0 +1,281 @@ +.file "logb.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 +//============================================================== +// 02/02/00 Initial version +// 02/16/00 Modified to conform to C9X +// 03/16/00 Improved speed +// 04/04/00 Unwind support added +// 05/30/00 Fixed bug when x double-extended denormal +// 08/15/00 Bundle added after call to __libm_error_support to properly +// set [the previously overwritten] GR_Parameter_RESULT. +// 05/20/02 Cleaned up namespace and sf0 syntax +// 01/20/03 Improved performance +// +// API +//============================================================== +// double logb( double x ); +// +// Overview of operation +//============================================================== +// The logb function extracts the exponent of x as an integer in +// floating-point format. +// logb computes log2 of x as a double +// +// logb is similar to ilogb but differs in the following ways: +// +-inf +// ilogb: returns INT_MAX +// logb: returns +inf +// Nan returns FP_LOGBNAN (which is either INT_MAX or INT_MIN) +// ilogb: returns INT_MAX (7fffffff) +// logb: returns QNAN (quietized SNAN) +// 0 returns FP_ILOGB0 (which is either INT_MIN or -INT_MAX) +// ilogb: returns -INT_MAX (80000001) +// logb: returns -inf, raises the divide-by-zero exception, +// and calls libm_error_support to set domain error +// +// Registers used +//============================================================== +// general registers used: +// r26 -> r38 +// r35 -> r38 used as parameters to error path +// +// predicate registers used: +// p6, p7, p8 +// floating-point registers used: +// f9, f10, f11 +// f8, input + +rExpBias = r26 +rExpMask = r27 +rSignexp_x = r28 +rExp_x = r29 +rTrueExp_x = r30 +rExp_2to64 = r31 + +GR_SAVE_PFS = r32 +GR_SAVE_B0 = r33 +GR_SAVE_GP = r34 + +GR_Parameter_X = r35 +GR_Parameter_Y = r36 +GR_Parameter_RESULT = r37 +GR_Parameter_TAG = r38 + +fExp_in_signif = f9 +fNorm_x = f10 +fFloat_Exp = f10 +f2to64 = f11 + +.section .text +GLOBAL_LIBM_ENTRY(logb) + +// X NORMAL +// TrueExp_x = exp(f8) - 0xffff +// sig = TrueExp_x +// f8 = convert_to_fp (sig)) +{ .mfi + getf.exp rSignexp_x = f8 + fclass.m p8,p0 = f8, 0x0b // Test for x unorm + mov rExpBias = 0xffff // Exponent bias +} +{ .mfi + nop.m 0 + fnorm.s1 fNorm_x = f8 + mov rExpMask = 0x1ffff // Exponent mask +} +;; + +// Form signexp of 2^64 in case need to scale denormal +{ .mfb + mov rExp_2to64 = 0x1003f + fclass.m p6,p0 = f8, 0x1e3 // Test x natval, nan, inf +(p8) br.cond.spnt LOGB_DENORM // Branch if x unorm +} +;; + +LOGB_COMMON: +// Return here from LOGB_DENORM +{ .mfi + and rExp_x = rSignexp_x, rExpMask // Get biased exponent + fclass.m p7,p0 = f8, 0x07 // Test x zero + nop.i 0 +} +;; + +// X NAN or INFINITY, return f8 * f8 +{ .mfb + sub rTrueExp_x = rExp_x, rExpBias // Get true exponent +(p6) fma.d.s0 f8= f8,f8,f0 // Result if x natval, nan, inf +(p6) br.ret.spnt b0 // Exit if x natval, nan, inf +} +;; + +{ .mib + setf.sig fExp_in_signif = rTrueExp_x // Exponent as integer in fp + nop.i 999 +(p7) br.cond.spnt LOGB_ZERO +} +;; + +// Result can be represented in less than 24 bits, so no precision completer +// is needed. +{ .mfb + nop.m 0 + fcvt.xf f8 = fExp_in_signif + br.ret.sptk b0 // Exit main path, 0 < |x| < inf +} +;; + +LOGB_DENORM: +// Form 2^64 in case need to scale denormal +// Check to see if double-extended denormal +{ .mfi + setf.exp f2to64 = rExp_2to64 + fclass.m p8,p0 = fNorm_x, 0x0b + nop.i 0 +} +;; + +{ .mfi + nop.m 0 + fcmp.eq.s0 p7,p0 = f8, f0 // Dummy op to set denormal flag + nop.i 0 +} +;; + +// If double-extended denormal add 64 to exponent bias for scaling +// If double-extended denormal form x * 2^64 which is normal +{ .mfi +(p8) add rExpBias = 64, rExpBias +(p8) fmpy.s1 fNorm_x = fNorm_x, f2to64 + nop.i 0 +} +;; + +// Logic is the same as normal path but use normalized input +{ .mib + getf.exp rSignexp_x = fNorm_x + nop.i 0 + br.cond.sptk LOGB_COMMON // Return to main path +} +;; + +LOGB_ZERO: +// Here if x zero +// f10 = -|f8| +// f9 = 1.0/f10 = -1.0/|f8| = -inf + +{ .mmf + alloc r32=ar.pfs,1,2,4,0 + mov GR_Parameter_TAG = 151 // Error code + fmerge.ns f10 = f0,f8 +} +;; + +{ .mfb + nop.m 0 + frcpa.s0 f9,p6 = f1,f10 // Produce -inf, Z flag + br.cond.sptk __libm_error_region // Call error support +} +;; + +GLOBAL_LIBM_END(logb) + + +LOCAL_LIBM_ENTRY(__libm_error_region) +.prologue + +{ .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 +};; + +{ .mmi + stfd [GR_Parameter_Y] = f0,16 // 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 +{ .mib + stfd [GR_Parameter_X] = 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] = f9 // 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 + add GR_Parameter_RESULT = 48,sp + nop.m 0 + nop.i 0 +};; + +{ .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 +};; + +LOCAL_LIBM_END(__libm_error_region) + + +.type __libm_error_support#,@function +.global __libm_error_support# |