diff options
Diffstat (limited to 'sysdeps/powerpc/powerpc32/fpu/s_roundf.S')
| -rw-r--r-- | sysdeps/powerpc/powerpc32/fpu/s_roundf.S | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/sysdeps/powerpc/powerpc32/fpu/s_roundf.S b/sysdeps/powerpc/powerpc32/fpu/s_roundf.S new file mode 100644 index 0000000000..ea8aaf3add --- /dev/null +++ b/sysdeps/powerpc/powerpc32/fpu/s_roundf.S @@ -0,0 +1,114 @@ +/* roundf function. PowerPC32 version. + Copyright (C) 2004 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, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <sysdep.h> + + .section .rodata + .align 3 + .type TWO23.0,@object + .size TWO23.0,8 +TWO23.0: + .long 0x43300000 + .long 0 + .type POINTFIVE.0,@object + .size POINTFIVE.0,8 +POINTFIVE.0: + .long 0x3fe00000 + .long 0 + .type NEGZERO.0,@object + .size NEGZERO.0,8 +NEGZERO.0: + .long 0x80000000 + .long 0 + + .section .rodata.cst8,"aM",@progbits,8 + .align 3 +.LC0: /* 2**23 */ + .long 0x41600000 + .long 0 +.LC1: /* 0.5 */ + .long 0x3fe00000 + .long 0 +.LC2: /* -0.0 */ + .long 0x80000000 + .long 0 + +/* float [fp1] roundf (float x [fp1]) + IEEE 1003.1 round 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. */ + +ENTRY (__roundf ) + mffs fp11 /* Save current FPU rounding mode. */ +#ifdef SHARED + mflr r11 + bl _GLOBAL_OFFSET_TABLE_@local-4 + mflr r10 + lwz r9,.LC0@got(10) + mtlr r11 + lfd fp13,0(r9) +#else + lis r9,.LC0@ha + lfd fp13,.LC0@l(r9) +#endif + fabs fp0,fp1 + fsubs fp12,fp13,fp13 /* generate 0.0 */ + fcmpu cr7,fp0,fp13 /* if (fabs(x) > TWO23) */ + fcmpu cr6,fp1,fp12 /* if (x > 0.0) */ + bnllr- cr7 + mtfsfi 7,1 /* Set rounding mode toward 0. */ +#ifdef SHARED + lwz r9,.LC1@got(10) + lfd fp10,0(r9) +#else + lis r9,.LC1@ha + lfd fp10,.LC1@l(r9) +#endif + ble- cr6,.L4 + fadds fp1,fp1,fp10 /* x+= 0.5; */ + fadds fp1,fp1,fp13 /* x+= TWO23; */ + fsubs fp1,fp1,fp13 /* x-= TWO23; */ +.L9: + mtfsf 0x01,fp11 /* restore previous rounding mode. */ + blr +.L4: + fsubs fp9,fp1,fp10 /* x+= 0.5; */ + bge- cr6,.L9 /* if (x < 0.0) */ + fsubs fp1,fp9,fp13 /* x-= TWO23; */ + fadds fp1,fp1,fp13 /* x+= TWO23; */ + fcmpu cr5,fp1,fp12 /* if (x > 0.0) */ + mtfsf 0x01,fp11 /* restore previous rounding mode. */ + bnelr+ cr5 +#ifdef SHARED + lwz r9,.LC2@got(10) + lfd fp1,0(r9) +#else + lis r9,.LC2@ha + lfd fp1,.LC2@l(r9) +#endif + blr + END (__roundf) + +weak_alias (__roundf, roundf) + |