.file "roundf.s" // Copyright (C) 2000, 2001, Intel Corporation // All rights reserved. // // Contributed 10/25/2000 by John Harrison, Cristina Iordache, Ted Kubaska, // Bob Norin, Tom Rowan, Shane Story, and Ping Tak Peter Tang of the // Computational Software Lab, 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://developer.intel.com/opensource. // // History //============================================================== // 10/25/2000: Created //============================================================== // // API //============================================================== // float roundf(float x) // #include "libm_support.h" // general input registers: // roundf_GR_half = r14 roundf_GR_big = r15 roundf_GR_expmask = r16 roundf_GR_signexp = r17 roundf_GR_exp = r18 roundf_GR_expdiff = r19 // predicate registers used: // p6 - p10 // floating-point registers used: ROUNDF_NORM_f8 = f9 ROUNDF_TRUNC_f8 = f10 ROUNDF_RINT_f8 = f11 ROUNDF_FLOAT_TRUNC_f8 = f12 ROUNDF_FLOAT_RINT_f8 = f13 ROUNDF_REMAINDER = f14 ROUNDF_HALF = f15 // Overview of operation //============================================================== // float roundf(float x) // Return an integer value (represented as a float) 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) // ******************************************************************************* // Set denormal flag for denormal input and // and take denormal fault if necessary. // If x is NAN, ZERO, INFINITY, or >= 2^23 then return // qnan snan inf norm unorm 0 -+ // 1 1 1 0 0 1 11 0xe7 .align 32 .global roundf# .section .text .proc roundf# .align 32 roundf: // Get exponent for +0.5 // Truncate x to integer { .mfi addl roundf_GR_half = 0x0fffe, r0 fcvt.fx.trunc.s1 ROUNDF_TRUNC_f8 = f8 nop.i 999 } // Get signexp of x // Normalize input // Form exponent mask { .mfi getf.exp roundf_GR_signexp = f8 fnorm ROUNDF_NORM_f8 = f8 addl roundf_GR_expmask = 0x1ffff, r0 ;; } // Form +0.5 // Round x to integer { .mfi setf.exp ROUNDF_HALF = roundf_GR_half fcvt.fx.s1 ROUNDF_RINT_f8 = f8 nop.i 999 ;; } // Get exp of x // Test for NAN, INF, ZERO // Get exponent at which input has no fractional part { .mfi and roundf_GR_exp = roundf_GR_expmask, roundf_GR_signexp fclass.m p8,p9 = f8,0xe7 addl roundf_GR_big = 0x10016, r0 ;; } // Get exp-bigexp // If exp is so big there is no fractional part, then turn on p8, off p9 { .mmi sub roundf_GR_expdiff = roundf_GR_exp, roundf_GR_big ;; #ifdef _LIBC (p9) cmp.lt.or.andcm p8,p9 = r0, roundf_GR_expdiff #else (p9) cmp.ge.or.andcm p8,p9 = roundf_GR_expdiff, r0 #endif nop.i 999 ;; } // Set p6 if x<0, else set p7 { .mfi nop.m 999 (p9) fcmp.lt.unc p6,p7 = f8,f0 nop.i 999 } // If NAN, INF, ZERO, or no fractional part, result is just normalized input { .mfi nop.m 999 (p8) fnorm.s.s0 f8 = f8 nop.i 999 ;; } // Float the truncated integer { .mfi nop.m 999 (p9) fcvt.xf ROUNDF_FLOAT_TRUNC_f8 = ROUNDF_TRUNC_f8 nop.i 999 ;; } // Float the rounded integer to get preliminary result { .mfi nop.m 999 (p9) fcvt.xf ROUNDF_FLOAT_RINT_f8 = ROUNDF_RINT_f8 nop.i 999 ;; } // If x<0 and the difference of the truncated input minus the input is 0.5 // then result = truncated input - 1.0 // Else if x>0 and the difference of the input minus truncated input is 0.5 // then result = truncated input + 1.0 // Else // result = rounded input // Endif { .mfi nop.m 999 (p6) fsub.s1 ROUNDF_REMAINDER = ROUNDF_FLOAT_TRUNC_f8, ROUNDF_NORM_f8 nop.i 999 } { .mfi nop.m 999 (p7) fsub.s1 ROUNDF_REMAINDER = ROUNDF_NORM_f8, ROUNDF_FLOAT_TRUNC_f8 nop.i 999 ;; } // Assume preliminary result is rounded integer { .mfi nop.m 999 (p9) fnorm.s.s0 f8 = ROUNDF_FLOAT_RINT_f8 nop.i 999 } // If x<0, test if result=0 { .mfi nop.m 999 (p6) fcmp.eq.unc p10,p0 = ROUNDF_FLOAT_RINT_f8,f0 nop.i 999 ;; } // If x<0 and result=0, set result=-0 { .mfi nop.m 999 (p10) fmerge.ns f8 = f1,f8 nop.i 999 } // If x<0, test if remainder=0.5 { .mfi nop.m 999 (p6) fcmp.eq.unc p6,p0 = ROUNDF_REMAINDER, ROUNDF_HALF nop.i 999 ;; } // If x>0, test if remainder=0.5 { .mfi nop.m 999 (p7) fcmp.eq.unc p7,p0 = ROUNDF_REMAINDER, ROUNDF_HALF nop.i 999 ;; } // If x<0 and remainder=0.5, result=truncated-1.0 // If x>0 and remainder=0.5, result=truncated+1.0 // Exit .pred.rel "mutex",p6,p7 { .mfi nop.m 999 (p6) fsub.s.s0 f8 = ROUNDF_FLOAT_TRUNC_f8,f1 nop.i 999 } { .mfb nop.m 999 (p7) fadd.s.s0 f8 = ROUNDF_FLOAT_TRUNC_f8,f1 br.ret.sptk b0 ;; } .endp roundf ASM_SIZE_DIRECTIVE(roundf)