From 6f0f237bf5a3c8d29a6342cbf8b4c17b10aa1d4c Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Fri, 18 Sep 2015 21:53:22 +0000 Subject: Avoid excess range in results from i386 exp, hypot, pow functions (bug 18980). i386 exp, hypot and pow functions can return overflowing and underflowing values with excess range and precision; ; Wilco Dijkstra's patches to make isfinite etc. expand inline cause this pre-existing issue to result in test failures. This patch fixes those functions to avoid excess range and precision in their return values. Appropriate macros are added for the repeated code sequences; in future I'll add more such macros and refactor existing code forcing underflow (with or without also eliminating excess range and precision from the return value) to use such macros. Tested for x86. If, after this patch, you still see x86 libm test failures with excess range or precision, please file bugs in Bugzilla. [BZ #18980] * sysdeps/i386/fpu/i386-math-asm.h (DEFINE_FLT_MIN): New macro. (DEFINE_DBL_MIN): Likewise. (FLT_NARROW_EVAL_UFLOW_NONNEG_NAN): Likewise. (DBL_NARROW_EVAL_UFLOW_NONNEG_NAN): Likewise. (FLT_NARROW_EVAL_UFLOW_NONNEG): Likewise. (DBL_NARROW_EVAL_UFLOW_NONNEG): Likewise. * sysdeps/i386/fpu/e_exp.S: Include . (dbl_min): Replace with use of DEFINE_DBL_MIN. (__ieee754_exp): Use DBL_NARROW_EVAL_UFLOW_NONNEG_NAN. (__exp_finite): Use DBL_NARROW_EVAL_UFLOW_NONNEG. * sysdeps/i386/fpu/e_exp10.S: Include . (dbl_min): Replace with use of DEFINE_DBL_MIN. (__ieee754_exp10): Use DBL_NARROW_EVAL_UFLOW_NONNEG_NAN. * sysdeps/i386/fpu/e_exp10f.S: Include . (flt_min): Replace with use of DEFINE_FLT_MIN. (__ieee754_exp10f): Use FLT_NARROW_EVAL_UFLOW_NONNEG_NAN. * sysdeps/i386/fpu/e_exp2.S: Include . (dbl_min): Replace with use of DEFINE_DBL_MIN. (__ieee754_exp2): Use DBL_NARROW_EVAL_UFLOW_NONNEG_NAN. * sysdeps/i386/fpu/e_exp2f.S: Include . (flt_min): Replace with use of DEFINE_FLT_MIN. (__ieee754_exp2f): Use FLT_NARROW_EVAL_UFLOW_NONNEG_NAN. * sysdeps/i386/fpu/e_expf.S: Include . (flt_min): Replace with use of DEFINE_FLT_MIN. (__ieee754_expf): Use FLT_NARROW_EVAL_UFLOW_NONNEG_NAN. (__expf_finite): Use FLT_NARROW_EVAL_UFLOW_NONNEG. * sysdeps/i386/fpu/e_hypot.S: Include . (__ieee754_hypot): Use DBL_NARROW_EVAL. * sysdeps/i386/fpu/e_hypotf.S: Include . (__ieee754_hypotf): Use FLT_NARROW_EVAL. * sysdeps/i386/fpu/e_pow.S: Include . (__ieee754_pow): Use DBL_NARROW_EVAL. * sysdeps/i386/fpu/e_powf.S: Include . (__ieee754_powf): Use FLT_NARROW_EVAL. * sysdeps/i386/i686/fpu/multiarch/e_expf-sse2.S (__ieee754_expf_sse2): Convert double-precision result to single precision. * sysdeps/i386/fpu/libm-test-ulps: Update. --- sysdeps/i386/fpu/e_exp10f.S | 26 ++++---------------------- 1 file changed, 4 insertions(+), 22 deletions(-) (limited to 'sysdeps/i386/fpu/e_exp10f.S') diff --git a/sysdeps/i386/fpu/e_exp10f.S b/sysdeps/i386/fpu/e_exp10f.S index a84b2ae535..1812b34398 100644 --- a/sysdeps/i386/fpu/e_exp10f.S +++ b/sysdeps/i386/fpu/e_exp10f.S @@ -3,13 +3,9 @@ */ #include +#include - .section .rodata.cst4,"aM",@progbits,4 - - .p2align 2 - .type flt_min,@object -flt_min: .byte 0, 0, 0x80, 0 - ASM_SIZE_DIRECTIVE(flt_min) +DEFINE_FLT_MIN #ifdef PIC # define MO(op) op##@GOTOFF(%ecx) @@ -45,22 +41,8 @@ ENTRY(__ieee754_exp10f) faddp /* 2^(fract(x * log2(10))) */ fscale /* e^x */ fstp %st(1) - flds MO(flt_min) - fld %st(1) - fucompp - fnstsw - sahf - jnc 3f - subl $4, %esp - cfi_adjust_cfa_offset (4) - fld %st(0) - fmul %st(0) - fstps (%esp) - fstps (%esp) - flds (%esp) - addl $4, %esp - cfi_adjust_cfa_offset (-4) -3: ret + FLT_NARROW_EVAL_UFLOW_NONNEG_NAN + ret 1: testl $0x200, %eax /* Test sign. */ jz 2f /* If positive, jump. */ -- cgit 1.4.1