Date: Tue, 30 Mar 2010 19:10:32 GMT From: dfilter@FreeBSD.ORG (dfilter service) To: freebsd-sparc64@FreeBSD.org Subject: Re: sparc64/144900: commit references a PR Message-ID: <201003301910.o2UJAWvN053319@freefall.freebsd.org>
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The following reply was made to PR sparc64/144900; it has been noted by GNATS. From: dfilter@FreeBSD.ORG (dfilter service) To: bug-followup@FreeBSD.org Cc: Subject: Re: sparc64/144900: commit references a PR Date: Tue, 30 Mar 2010 19:09:07 +0000 (UTC) Author: marius Date: Tue Mar 30 19:08:05 2010 New Revision: 205903 URL: http://svn.freebsd.org/changeset/base/205903 Log: MFC: r205397 - While SPARC V9 allows tininess to be detected either before or after rounding (impl. dep. #55), the SPARC JPS1 responsible for SPARC64 and UltraSPARC processors defines that in all cases tinyness is detected before rounding, therefore rounding up to the smallest normalised number should set the underflow flag. - If an infinite result is rounded down, the result should have an exponent 1 less than the value for infinity. PR: 144900 Submitted by: Peter Jeremy Modified: stable/6/lib/libc/sparc64/fpu/fpu_implode.c Directory Properties: stable/6/lib/libc/ (props changed) Modified: stable/6/lib/libc/sparc64/fpu/fpu_implode.c ============================================================================== --- stable/6/lib/libc/sparc64/fpu/fpu_implode.c Tue Mar 30 19:08:02 2010 (r205902) +++ stable/6/lib/libc/sparc64/fpu/fpu_implode.c Tue Mar 30 19:08:05 2010 (r205903) @@ -333,8 +333,9 @@ __fpu_ftos(fe, fp) * right to introduce leading zeroes. Rounding then acts * differently for normals and subnormals: the largest subnormal * may round to the smallest normal (1.0 x 2^minexp), or may - * remain subnormal. In the latter case, signal an underflow - * if the result was inexact or if underflow traps are enabled. + * remain subnormal. A number that is subnormal before rounding + * will signal an underflow if the result is inexact or if underflow + * traps are enabled. * * Rounding a normal, on the other hand, always produces another * normal (although either way the result might be too big for @@ -349,8 +350,10 @@ __fpu_ftos(fe, fp) if ((exp = fp->fp_exp + SNG_EXP_BIAS) <= 0) { /* subnormal */ /* -NG for g,r; -SNG_FRACBITS-exp for fraction */ (void) __fpu_shr(fp, FP_NMANT - FP_NG - SNG_FRACBITS - exp); - if (fpround(fe, fp) && fp->fp_mant[3] == SNG_EXP(1)) + if (fpround(fe, fp) && fp->fp_mant[3] == SNG_EXP(1)) { + fe->fe_cx |= FSR_UF; return (sign | SNG_EXP(1) | 0); + } if ((fe->fe_cx & FSR_NX) || (fe->fe_fsr & (FSR_UF << FSR_TEM_SHIFT))) fe->fe_cx |= FSR_UF; @@ -411,6 +414,7 @@ zero: res[1] = 0; if ((exp = fp->fp_exp + DBL_EXP_BIAS) <= 0) { (void) __fpu_shr(fp, FP_NMANT - FP_NG - DBL_FRACBITS - exp); if (fpround(fe, fp) && fp->fp_mant[2] == DBL_EXP(1)) { + fe->fe_cx |= FSR_UF; res[1] = 0; return (sign | DBL_EXP(1) | 0); } @@ -430,7 +434,7 @@ zero: res[1] = 0; return (sign | DBL_EXP(DBL_EXP_INFNAN) | 0); } res[1] = ~0; - return (sign | DBL_EXP(DBL_EXP_INFNAN) | DBL_MASK); + return (sign | DBL_EXP(DBL_EXP_INFNAN - 1) | DBL_MASK); } done: res[1] = fp->fp_mant[3]; @@ -472,6 +476,7 @@ zero: res[1] = res[2] = res[3] = 0; if ((exp = fp->fp_exp + EXT_EXP_BIAS) <= 0) { (void) __fpu_shr(fp, FP_NMANT - FP_NG - EXT_FRACBITS - exp); if (fpround(fe, fp) && fp->fp_mant[0] == EXT_EXP(1)) { + fe->fe_cx |= FSR_UF; res[1] = res[2] = res[3] = 0; return (sign | EXT_EXP(1) | 0); } @@ -491,7 +496,7 @@ zero: res[1] = res[2] = res[3] = 0; return (sign | EXT_EXP(EXT_EXP_INFNAN) | 0); } res[1] = res[2] = res[3] = ~0; - return (sign | EXT_EXP(EXT_EXP_INFNAN) | EXT_MASK); + return (sign | EXT_EXP(EXT_EXP_INFNAN - 1) | EXT_MASK); } done: res[1] = fp->fp_mant[1]; _______________________________________________ svn-src-all@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscribe@freebsd.org"
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