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Diffstat (limited to 'REORG.TODO/sysdeps/powerpc/powerpc32/power4/fpu/s_llround.S')
| -rw-r--r-- | REORG.TODO/sysdeps/powerpc/powerpc32/power4/fpu/s_llround.S | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/powerpc/powerpc32/power4/fpu/s_llround.S b/REORG.TODO/sysdeps/powerpc/powerpc32/power4/fpu/s_llround.S new file mode 100644 index 0000000000..24bd533748 --- /dev/null +++ b/REORG.TODO/sysdeps/powerpc/powerpc32/power4/fpu/s_llround.S @@ -0,0 +1,106 @@ +/* llround function. PowerPC32 on PowerPC64 version. + Copyright (C) 2004-2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#include <sysdep.h> +#include <math_ldbl_opt.h> + + .section .rodata.cst8,"aM",@progbits,8 + .align 3 + .LC0: .long (52+127)<<23 /* 0x1p+52 */ + .long (-1+127)<<23 /* 0.5 */ + + .section ".text" + +/* long [r3] lround (float x [fp1]) + IEEE 1003.1 lround function. IEEE specifies "round to the nearest + integer value, rounding halfway cases away from zero, regardless of + the current rounding mode." However PowerPC Architecture defines + "round to Nearest" as "Choose the best approximation. In case of a + tie, choose the one that is even (least significant bit o).". + So we can't use the PowerPC "round to Nearest" mode. Instead we set + "round toward Zero" mode and round by adding +-0.5 before rounding + to the integer value. + + It is necessary to detect when x is (+-)0x1.fffffffffffffp-2 + because adding +-0.5 in this case will cause an erroneous shift, + carry and round. We simply return 0 if 0.5 > x > -0.5. Likewise + if x is and odd number between +-(2^52 and 2^53-1) a shift and + carry will erroneously round if biased with +-0.5. Therefore if x + is greater/less than +-2^52 we don't need to bias the number with + +-0.5. */ + +ENTRY (__llround) + stwu r1,-16(r1) + cfi_adjust_cfa_offset (16) +#ifdef SHARED + mflr r11 + cfi_register(lr,r11) + SETUP_GOT_ACCESS(r9,got_label) + addis r9,r9,.LC0-got_label@ha + addi r9,r9,.LC0-got_label@l + mtlr r11 + cfi_same_value (lr) + lfs fp9,0(r9) + lfs fp10,4(r9) +#else + lis r9,.LC0@ha + lfs fp9,.LC0@l(r9) /* Load 2^52 into fpr9. */ + lfs fp10,.LC0@l+4(r9) /* Load 0.5 into fpr10. */ +#endif + fabs fp2,fp1 /* Get the absolute value of x. */ + fsub fp12,fp10,fp10 /* Compute 0.0 into fpr12. */ + fcmpu cr6,fp2,fp10 /* if |x| < 0.5 */ + fcmpu cr7,fp2,fp9 /* if |x| >= 2^52 */ + fcmpu cr1,fp1,fp12 /* x is negative? x < 0.0 */ + blt- cr6,.Lretzero /* 0.5 > x < -0.5 so just return 0. */ + bge- cr7,.Lnobias /* 2^52 > x < -2^52 just convert with no bias. */ + fadd fp3,fp2,fp10 /* |x|+=0.5 bias to prepare to round. */ + bge cr1,.Lconvert /* x is positive so don't negate x. */ + fnabs fp3,fp3 /* -(|x|+=0.5) */ +.Lconvert: + fctidz fp4,fp3 /* Convert to Integer double word round toward 0. */ + stfd fp4,8(r1) + nop + nop + nop + lwz r3,8+HIWORD(r1) /* Load return as integer. */ + lwz r4,8+LOWORD(r1) +.Lout: + addi r1,r1,16 + blr +.Lretzero: /* 0.5 > x > -0.5 */ + li r3,0 /* return 0. */ + li r4,0 + b .Lout +.Lnobias: + fmr fp3,fp1 + b .Lconvert + END (__llround) + +weak_alias (__llround, llround) + +strong_alias (__llround, __llroundf) +weak_alias (__llround, llroundf) + +#ifdef NO_LONG_DOUBLE +weak_alias (__llround, llroundl) +strong_alias (__llround, __llroundl) +#endif +#if LONG_DOUBLE_COMPAT(libm, GLIBC_2_1) +compat_symbol (libm, __llround, llroundl, GLIBC_2_1) +#endif |