diff options
| -rw-r--r-- | ChangeLog | 14 | ||||
| -rw-r--r-- | math/libm-test.inc | 43 | ||||
| -rw-r--r-- | sysdeps/powerpc/powerpc32/fpu/s_lround.S | 52 | ||||
| -rw-r--r-- | sysdeps/powerpc/powerpc32/power4/fpu/s_llround.S | 71 | ||||
| -rw-r--r-- | sysdeps/powerpc/powerpc64/fpu/s_llround.S | 57 | ||||
| -rw-r--r-- | sysdeps/powerpc/powerpc64/fpu/s_llroundf.S | 53 |
6 files changed, 203 insertions, 87 deletions
diff --git a/ChangeLog b/ChangeLog index dc385f2d8d..d60b35a9da 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,17 @@ +2007-11-20 Ryan S. Arnold <rsa@us.ibm.com> + + [BZ4997] + * sysdeps/powerpc/powerpc32/fpu/s_lround.S (__lround): Fixed erroneous + result when x is +/-nextafter(+/-0.5,-/+1) i.e. all 1's in the + mantissa. + * sysdeps/powerpc/powerpc32/power4/fpu/s_llround.S (__llround): + Likewise. Also account for when x is an odd number between 2^52 + and 2^53-1. + * sysdeps/powerpc/powerpc64/fpu/s_llround.S (__llround): Likewise. + * sysdeps/powerpc/powerpc64/fpu/s_llroundf.S (__llroundf): Likewise. + * math/libm-test.inc (lround_test, llround_test): Added test cases to + detect aforementioned erroneous conditions. + 2008-04-11 Jakub Jelinek <jakub@redhat.com> * configure.in: Check for -fno-section-anchors in addition to diff --git a/math/libm-test.inc b/math/libm-test.inc index a33a182857..b8a73ae1f6 100644 --- a/math/libm-test.inc +++ b/math/libm-test.inc @@ -4300,6 +4300,17 @@ lround_test (void) # endif TEST_f_l (lround, 2097152.5, 2097153); TEST_f_l (lround, -2097152.5, -2097153); + /* nextafter(0.5,-1) */ + TEST_f_l (lround, 0x1.fffffffffffffp-2, 0); + /* nextafter(-0.5,1) */ + TEST_f_l (lround, -0x1.fffffffffffffp-2, 0); +#else + /* nextafter(0.5,-1) */ + TEST_f_l (lround, 0x1.fffffp-2, 0); + /* nextafter(-0.5,1) */ + TEST_f_l (lround, -0x1.fffffp-2, 0); + TEST_f_l (lround, 0x1.fffffep+23, 16777215); + TEST_f_l (lround, -0x1.fffffep+23, -16777215); #endif END (lround); } @@ -4359,8 +4370,40 @@ llround_test (void) TEST_f_L (llround, 4294967295.5, 4294967296LL); /* 0x200000000 */ TEST_f_L (llround, 8589934591.5, 8589934592LL); + + /* nextafter(0.5,-1) */ + TEST_f_L (llround, 0x1.fffffffffffffp-2, 0); + /* nextafter(-0.5,1) */ + TEST_f_L (llround, -0x1.fffffffffffffp-2, 0); + /* On PowerPC an exponent of '52' is the largest incrementally + * representable sequence of whole-numbers in the 'double' range. We test + * lround to make sure that a guard bit set during the lround operation + * hasn't forced an erroneous shift giving us an incorrect result. The odd + * numbers between +-(2^52+1 and 2^53-1) are affected since they have the + * rightmost bit set. */ + /* +-(2^52+1) */ + TEST_f_L (llround, 0x1.0000000000001p+52,4503599627370497LL); + TEST_f_L (llround, -0x1.0000000000001p+52,-4503599627370497LL); + /* +-(2^53-1): Input is the last (positive and negative) incrementally + * representable whole-number in the 'double' range that might round + * erroneously. */ + TEST_f_L (llround, 0x1.fffffffffffffp+52, 9007199254740991LL); + TEST_f_L (llround, -0x1.fffffffffffffp+52, -9007199254740991LL); +#else + /* nextafter(0.5,-1) */ + TEST_f_L (llround, 0x1.fffffep-2, 0); + /* nextafter(-0.5,1) */ + TEST_f_L (llround, -0x1.fffffep-2, 0); + /* As above, on PowerPC an exponent of '23' is the largest incrementally + * representable sequence of whole-numbers in the 'float' range. + * Likewise, numbers between +-(2^23+1 and 2^24-1) are affected. */ + TEST_f_L (llround, 0x1.000002p+23,8388609); + TEST_f_L (llround, -0x1.000002p+23,-8388609); + TEST_f_L (llround, 0x1.fffffep+23, 16777215); + TEST_f_L (llround, -0x1.fffffep+23, -16777215); #endif + #ifdef TEST_LDOUBLE /* The input can only be represented in long double. */ TEST_f_L (llround, 4503599627370495.5L, 4503599627370496LL); diff --git a/sysdeps/powerpc/powerpc32/fpu/s_lround.S b/sysdeps/powerpc/powerpc32/fpu/s_lround.S index 9c534ec2be..ebaccccd9b 100644 --- a/sysdeps/powerpc/powerpc32/fpu/s_lround.S +++ b/sysdeps/powerpc/powerpc32/fpu/s_lround.S @@ -1,5 +1,5 @@ /* lround function. PowerPC32 version. - Copyright (C) 2004, 2006 Free Software Foundation, Inc. + Copyright (C) 2004, 2006, 2007 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 @@ -20,13 +20,10 @@ #include <sysdep.h> #include <math_ldbl_opt.h> - .section .rodata.cst8,"aM",@progbits,8 + .section .rodata.cst4,"aM",@progbits,4 .align 2 -.LC0: /* 0.0 */ - .long 0x00000000 -.LC1: /* 0.5 */ +.LC0: /* 0.5 */ .long 0x3f000000 - .section ".text" /* long [r3] lround (float x [fp1]) @@ -37,7 +34,10 @@ 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. */ + 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. */ ENTRY (__lround) stwu r1,-16(r1) @@ -49,40 +49,40 @@ ENTRY (__lround) bcl 20,31,1f 1: mflr r9 addis r9,r9,.LC0-1b@ha - addi r9,r9,.LC0-1b@l + lfs fp10,.LC0-1b@l(r9) # else bl _GLOBAL_OFFSET_TABLE_@local-4 mflr r10 lwz r9,.LC0@got(10) + lfs fp10,0(r9) # endif mtlr r11 cfi_same_value (lr) - lfs fp12,0(r9) #else lis r9,.LC0@ha - lfs fp12,.LC0@l(r9) -#endif -#ifdef SHARED - lfs fp10,.LC1-.LC0(r9) -#else - lis r9,.LC1@ha - lfs fp10,.LC1@l(r9) + lfs fp10,.LC0@l(r9) #endif - fcmpu cr6,fp1,fp12 /* if (x > 0.0) */ - ble- cr6,.L4 - fadd fp1,fp1,fp10 /* x+= 0.5; */ -.L9: - fctiwz fp2,fp1 /* Convert To Integer DW lround toward 0. */ - stfd fp2,8(r1) + fabs fp2, fp1 /* Get the absolute value of x. */ + fsub fp12,fp10,fp10 /* Compute 0.0. */ + fcmpu cr6, fp2, fp10 /* if |x| < 0.5 */ + fcmpu cr3, fp1, fp12 /* x is negative? x < 0.0 */ + blt- cr6,.Lretzero + fadd fp3,fp2,fp10 /* |x|+=0.5 bias to prepare to round. */ + bge cr3,.Lconvert /* x is positive so don't negate x. */ + fnabs fp3,fp3 /* -(|x|+=0.5) */ +.Lconvert: + fctiwz fp4,fp3 /* Convert to Integer word lround toward 0. */ + stfd fp4,8(r1) nop /* Ensure the following load is in a different dispatch */ nop /* group to avoid pipe stall on POWER4&5. */ nop - lwz r3,12(r1) + lwz r3,12(r1) /* Load return as integer. */ +.Lout: addi r1,r1,16 blr -.L4: - fsub fp1,fp1,fp10 /* x-= 0.5; */ - b .L9 +.Lretzero: /* when 0.5 > x > -0.5 */ + li r3,0 /* return 0. */ + b .Lout END (__lround) weak_alias (__lround, lround) diff --git a/sysdeps/powerpc/powerpc32/power4/fpu/s_llround.S b/sysdeps/powerpc/powerpc32/power4/fpu/s_llround.S index 952d2aa6a5..4b1691efd3 100644 --- a/sysdeps/powerpc/powerpc32/power4/fpu/s_llround.S +++ b/sysdeps/powerpc/powerpc32/power4/fpu/s_llround.S @@ -1,5 +1,5 @@ /* llround function. PowerPC32 on PowerPC64 version. - Copyright (C) 2004, 2006 Free Software Foundation, Inc. + Copyright (C) 2004, 2006, 2007 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 @@ -20,15 +20,15 @@ #include <sysdep.h> #include <math_ldbl_opt.h> - .section .rodata.cst8,"aM",@progbits,8 - .align 2 -.LC0: /* 0.0 */ + .section .rodata.cst12,"aM",@progbits,12 + .align 3 + .LC0: /* 0x1.0000000000000p+52 == 2^52 */ + .long 0x43300000 .long 0x00000000 -.LC1: /* 0.5 */ - .long 0x3f000000 + .long 0x3f000000 /* Use this for 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 @@ -37,7 +37,15 @@ 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. */ + 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) @@ -57,30 +65,41 @@ ENTRY (__llround) # endif mtlr r11 cfi_same_value (lr) - lfs fp12,0(r9) - lfs fp10,.LC1-.LC0(r9) + lfd fp9,0(r9) + lfs fp10,8(r9) #else - lis r9,.LC0@ha - lis r10,.LC1@ha - lfs fp12,.LC0@l(r9) - lfs fp10,.LC1@l(r10) + lis r9,.LC0@ha + lfd fp9,.LC0@l(r9) /* Load 2^52 into fpr9. */ + lfs fp10,.LC0@l+8(r9) /* Load 0.5 into fpr10. */ #endif - fcmpu cr6,fp1,fp12 /* if (x > 0.0) */ - ble- cr6,.L4 - fadd fp1,fp1,fp10 /* x+= 0.5; */ -.L9: - fctidz fp2,fp1 /* Convert To Integer DW round toward 0. */ - stfd fp2,8(r1) - nop /* Ensure the following load is in a different dispatch */ - nop /* group to avoid pipe stall on POWER4&5. */ + 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 cr4,fp2,fp9 /* if |x| >= 2^52 */ + fcmpu cr3,fp1,fp12 /* x is negative? x < 0.0 */ + blt- cr6,.Lretzero /* 0.5 > x < -0.5 so just return 0. */ + bge- cr4,.Lnobias /* 2^52 > x < -2^52 just convert with no bias. */ + fadd fp3,fp2,fp10 /* |x|+=0.5 bias to prepare to round. */ + bge cr3,.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 r4,12(r1) + lwz r4,12(r1) /* Load return as integer. */ lwz r3,8(r1) +.Lout: addi r1,r1,16 blr -.L4: - fsub fp1,fp1,fp10 /* x-= 0.5; */ - b .L9 +.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) diff --git a/sysdeps/powerpc/powerpc64/fpu/s_llround.S b/sysdeps/powerpc/powerpc64/fpu/s_llround.S index d023b8f2c0..4134847536 100644 --- a/sysdeps/powerpc/powerpc64/fpu/s_llround.S +++ b/sysdeps/powerpc/powerpc64/fpu/s_llround.S @@ -1,5 +1,5 @@ /* llround function. PowerPC64 version. - Copyright (C) 2004, 2006 Free Software Foundation, Inc. + Copyright (C) 2004, 2006, 2007 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 @@ -21,13 +21,13 @@ #include <math_ldbl_opt.h> .section ".toc","aw" -.LC0: /* -0.0 */ - .tc FD_00000000_0[TC],0x0000000000000000 +.LC0: /* 2^52 */ + .tc FD_43300000_0[TC],0x4330000000000000 .LC1: /* 0.5 */ .tc FD_3fe00000_0[TC],0x3fe0000000000000 .section ".text" -/* long long [r3] llround (float x [fp1]) +/* long long [r3] llround (double x [fp1]) IEEE 1003.1 llround 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 @@ -35,26 +35,45 @@ 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. */ + 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) CALL_MCOUNT 0 - lfd fp12,.LC0@toc(2) - lfd fp10,.LC1@toc(2) - fcmpu cr6,fp1,fp12 /* if (x > 0.0) */ - ble- cr6,.L4 - fadd fp1,fp1,fp10 /* x+= 0.5; */ -.L9: - fctidz fp2,fp1 /* Convert To Integer DW llround toward 0. */ - stfd fp2,-16(r1) - nop /* Insure the following load is in a different dispatch group */ - nop /* to avoid pipe stall on POWER4&5. */ + lfd fp9,.LC0@toc(2) /* Load 2^52 into fpr9. */ + lfd fp10,.LC1@toc(2)/* Load 0.5 into fpr10. */ + fabs fp2,fp1 /* Get the absolute value of x. */ + fsub fp12,fp10,fp10 /* Compute 0.0 into fp12. */ + fcmpu cr6,fp2,fp10 /* if |x| < 0.5 */ + fcmpu cr4,fp2,fp9 /* if |x| >= 2^52 */ + fcmpu cr3,fp1,fp12 /* x is negative? x < 0.0 */ + blt- cr6,.Lretzero /* 0.5 > x < -0.5 so just return 0. */ + bge- cr4,.Lnobias /* 2^52 > x < -2^52 just convert with no bias. */ + fadd fp3,fp2,fp10 /* |x|+=0.5 bias to prepare to round. */ + bge cr3,.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,-16(r1) + nop + nop nop - ld r3,-16(r1) + ld r3,-16(r1) /* Load return as integer. */ +.Lout: blr -.L4: - fsub fp1,fp1,fp10 /* x-= 0.5; */ - b .L9 +.Lretzero: /* 0.5 > x > -0.5 */ + li r3,0 /* return 0. */ + b .Lout +.Lnobias: + fmr fp3,fp1 + b .Lconvert END (__llround) strong_alias (__llround, __lround) diff --git a/sysdeps/powerpc/powerpc64/fpu/s_llroundf.S b/sysdeps/powerpc/powerpc64/fpu/s_llroundf.S index bbbd05492e..a211879393 100644 --- a/sysdeps/powerpc/powerpc64/fpu/s_llroundf.S +++ b/sysdeps/powerpc/powerpc64/fpu/s_llroundf.S @@ -1,5 +1,5 @@ /* llroundf function. PowerPC64 version. - Copyright (C) 2004, 2006 Free Software Foundation, Inc. + Copyright (C) 2004, 2006, 2007 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 @@ -20,8 +20,8 @@ #include <sysdep.h> .section ".toc","aw" -.LC0: /* -0.0 */ - .tc FD_00000000_0[TC],0x0000000000000000 +.LC0: /* 2^23 */ + .tc FD_41600000_0[TC],0x4160000000000000 .LC1: /* 0.5 */ .tc FD_3fe00000_0[TC],0x3fe0000000000000 .section ".text" @@ -34,24 +34,45 @@ 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. */ + 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 +-(2^23 and 2^24-1) a shift and + carry will erroneously round if biased with +-0.5. Therefore if x + is greater/less than +-2^23 we don't need to bias the number with + +-0.5. */ ENTRY (__llroundf) CALL_MCOUNT 0 - lfd fp12,.LC0@toc(2) - lfd fp10,.LC1@toc(2) - fcmpu cr6,fp1,fp12 /* if (x < 0.0) */ - fsubs fp3,fp1,fp10 /* x-= 0.5; */ - ble- cr6,.L9 - fadds fp3,fp1,fp10 /* x+= 0.5; */ -.L9: - fctidz fp2,fp3 /* Convert To Integer DW round toward 0. */ - stfd fp2,-16(r1) - nop /* Insure the following load is in a different dispatch group */ - nop /* to avoid pipe stall on POWER4&5. */ + lfd fp9,.LC0@toc(2) /* Load 2^23 into fpr9. */ + lfd fp10,.LC1@toc(2)/* Load 0.5 into fpr10. */ + fabs fp2,fp1 /* Get the absolute value of x. */ + fsub fp12,fp10,fp10 /* Compute 0.0 into fp12. */ + fcmpu cr6,fp2,fp10 /* if |x| < 0.5 */ + fcmpu cr4,fp2,fp9 /* if |x| >= 2^23 */ + fcmpu cr3,fp1,fp12 /* x is negative? x < 0.0 */ + blt- cr6,.Lretzero /* 0.5 > x < -0.5 so just return 0. */ + bge- cr4,.Lnobias /* 2^23 > x < -2^23 just convert with no bias. */ + fadd fp3,fp2,fp10 /* |x|+=0.5 bias to prepare to round. */ + bge cr3,.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,-16(r1) + nop + nop nop - ld r3,-16(r1) + ld r3,-16(r1) /* Load return as integer. */ +.Lout: blr +.Lretzero: /* 0.5 > x > -0.5 */ + li r3,0 /* return 0. */ + b .Lout +.Lnobias: + fmr fp3,fp1 + b .Lconvert END (__llroundf) strong_alias (__llroundf, __lroundf) |