From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 32355 invoked by alias); 24 Apr 2013 17:40:55 -0000 Mailing-List: contact libc-ports-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: libc-ports-owner@sourceware.org Received: (qmail 32336 invoked by uid 89); 24 Apr 2013 17:40:54 -0000 X-Spam-SWARE-Status: No, score=-3.7 required=5.0 tests=AWL,BAYES_00,KHOP_RCVD_UNTRUST,RCVD_IN_HOSTKARMA_W,RCVD_IN_HOSTKARMA_WL,TW_SF autolearn=ham version=3.3.1 X-Spam-User: qpsmtpd, 2 recipients Received: from relay1.mentorg.com (HELO relay1.mentorg.com) (192.94.38.131) by sourceware.org (qpsmtpd/0.84/v0.84-167-ge50287c) with ESMTP; Wed, 24 Apr 2013 17:40:53 +0000 Received: from svr-orw-exc-10.mgc.mentorg.com ([147.34.98.58]) by relay1.mentorg.com with esmtp id 1UV3ga-0000Di-3Q from Maciej_Rozycki@mentor.com ; Wed, 24 Apr 2013 10:40:52 -0700 Received: from SVR-IES-FEM-01.mgc.mentorg.com ([137.202.0.104]) by SVR-ORW-EXC-10.mgc.mentorg.com with Microsoft SMTPSVC(6.0.3790.4675); Wed, 24 Apr 2013 10:40:53 -0700 Received: from [172.30.64.177] (137.202.0.76) by SVR-IES-FEM-01.mgc.mentorg.com (137.202.0.104) with Microsoft SMTP Server id 14.2.247.3; Wed, 24 Apr 2013 18:40:49 +0100 Date: Wed, 24 Apr 2013 17:40:00 -0000 From: "Maciej W. Rozycki" To: CC: Subject: [PATCH] MIPS/glibc: soft-fp NaN representation corrections Message-ID: User-Agent: Alpine 1.10 (DEB 962 2008-03-14) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" X-SW-Source: 2013-04/txt/msg00101.txt.bz2 Hi, Unlike many platforms traditional MIPS targets interpret the quiet bit of NaN data in the inverse way, a NaN is quiet whenever the bit is clear. Additionally the canonical qNaN encoding has all the payload bits set rather than clear. The quiet bit convention is however currently not respected by our soft-fp implementation. Here's a suitable change to correct it. The changes are extensive, however the only use by the MIPS target within glibc is sqrtl on the new ABIs (I have an outstanding change to make GCC's copy of soft-fp used in a more extensive manner though). I have manually verified that this change has the desired effect on that function, both with the n64 and the n32 ABI and both endiannesses each. The o32 version of sfp-machine.h appears unused, however I changed it for correctness regardless (perhaps the file should be dropped). For the sake of readability and ease of maintenance I decided to factor out both raw (_FP_FRAC_SNANP, _FP_SETQNAN) and semi-raw (_FP_FRAC_SNANP_SEMIRAW, _FP_SETQNAN_SEMIRAW) macros even though the latters are only used once each. These changes touch generic code, for the most part. They are supposed not to affect targets other than MIPS, however I think it would make sense to test them at least on a selection of other targets glibc supports. However I am not familiar enough with other targets to know how much soft-fp is used across them; also I think automatic testing may have a better value than manually poking at a function or three. I will therefore appreciate ideas as to how to test these changes, or any other help with that indeed. Otherwise, do these changes look OK? 2013-04-24 Maciej W. Rozycki / * soft-fp/op-common.h (_FP_FRAC_SNANP): New macro. (_FP_FRAC_SNANP_SEMIRAW): Likewise. (_FP_UNPACK_CANONICAL): Use _FP_FRAC_SNANP. (_FP_CHECK_SIGNAN_SEMIRAW): Use _FP_FRAC_SNANP_SEMIRAW. (_FP_SETQNAN): New macro. (_FP_SETQNAN_SEMIRAW): Likewise. (_FP_PACK_SEMIRAW): Use _FP_SETQNAN. (_FP_PACK_CANONICAL): Use _FP_SETQNAN. (_FP_ISSIGNAN): Use _FP_FRAC_SNANP. (FP_EXTEND): Use _FP_FRAC_SNANP. (FP_TRUNC): Use _FP_SETQNAN_SEMIRAW. * soft-fp/testit.c (gen_special_double): Take _FP_QNANNEGATEDP into account. * sysdeps/sparc/sparc32/soft-fp/sfp-machine.h (_FP_QNANNEGATEDP): New macro. * sysdeps/sparc/sparc64/soft-fp/sfp-machine.h (_FP_QNANNEGATEDP): Likewise. ports/ * sysdeps/mips/mips64/soft-fp/sfp-machine.h (_FP_QNANNEGATEDP): New macro. (_FP_NANFRAC_S): Don't set the quiet bit. (_FP_NANFRAC_D): Likewise. (_FP_NANFRAC_Q): Likewise. * sysdeps/mips/soft-fp/sfp-machine.h (_FP_QNANNEGATEDP): New macro. (_FP_NANFRAC_S): Don't set the quiet bit. (_FP_NANFRAC_D): Likewise. (_FP_NANFRAC_Q): Likewise. * sysdeps/aarch64/soft-fp/sfp-machine.h (_FP_QNANNEGATEDP): New macro. * sysdeps/alpha/soft-fp/sfp-machine.h (_FP_QNANNEGATEDP): Likewise. * sysdeps/powerpc/soft-fp/sfp-machine.h (_FP_QNANNEGATEDP): New macro. Maciej glibc-mips-soft-fp-nan.diff Index: glibc-fsf-trunk-quilt/ports/sysdeps/aarch64/soft-fp/sfp-machine.h =================================================================== --- glibc-fsf-trunk-quilt.orig/ports/sysdeps/aarch64/soft-fp/sfp-machine.h 2013-04-23 00:28:50.097012113 +0100 +++ glibc-fsf-trunk-quilt/ports/sysdeps/aarch64/soft-fp/sfp-machine.h 2013-04-23 00:33:47.108144185 +0100 @@ -25,6 +25,8 @@ #define _FP_NANSIGN_Q 0 #define _FP_KEEPNANFRACP 1 +#define _FP_QNANNEGATEDP 0 + /* From my experiments it seems X is chosen unless one of the NaNs is sNaN, in which case the result is NANSIGN/NANFRAC. */ #define _FP_CHOOSENAN(fs, wc, R, X, Y, OP) \ Index: glibc-fsf-trunk-quilt/ports/sysdeps/alpha/soft-fp/sfp-machine.h =================================================================== --- glibc-fsf-trunk-quilt.orig/ports/sysdeps/alpha/soft-fp/sfp-machine.h 2013-04-23 00:28:50.097012113 +0100 +++ glibc-fsf-trunk-quilt/ports/sysdeps/alpha/soft-fp/sfp-machine.h 2013-04-23 00:33:47.108144185 +0100 @@ -46,6 +46,7 @@ #define _FP_NANSIGN_Q 0 #define _FP_KEEPNANFRACP 1 +#define _FP_QNANNEGATEDP 0 /* Alpha Architecture Handbook, 4.7.10.4 sez that we should prefer any type of NaN in Fb, then Fa. */ Index: glibc-fsf-trunk-quilt/ports/sysdeps/mips/mips64/soft-fp/sfp-machine.h =================================================================== --- glibc-fsf-trunk-quilt.orig/ports/sysdeps/mips/mips64/soft-fp/sfp-machine.h 2013-04-23 00:28:50.097012113 +0100 +++ glibc-fsf-trunk-quilt/ports/sysdeps/mips/mips64/soft-fp/sfp-machine.h 2013-04-23 00:33:47.108144185 +0100 @@ -17,14 +17,16 @@ #define _FP_DIV_MEAT_D(R,X,Y) _FP_DIV_MEAT_1_udiv_norm(D,R,X,Y) #define _FP_DIV_MEAT_Q(R,X,Y) _FP_DIV_MEAT_2_udiv(Q,R,X,Y) -#define _FP_NANFRAC_S ((_FP_QNANBIT_S << 1) - 1) -#define _FP_NANFRAC_D ((_FP_QNANBIT_D << 1) - 1) -#define _FP_NANFRAC_Q ((_FP_QNANBIT_Q << 1) - 1), -1 +#define _FP_NANFRAC_S (_FP_QNANBIT_S - 1) +#define _FP_NANFRAC_D (_FP_QNANBIT_D - 1) +#define _FP_NANFRAC_Q (_FP_QNANBIT_Q - 1), -1 #define _FP_NANSIGN_S 0 #define _FP_NANSIGN_D 0 #define _FP_NANSIGN_Q 0 #define _FP_KEEPNANFRACP 1 +#define _FP_QNANNEGATEDP 1 + /* From my experiments it seems X is chosen unless one of the NaNs is sNaN, in which case the result is NANSIGN/NANFRAC. */ #define _FP_CHOOSENAN(fs, wc, R, X, Y, OP) \ Index: glibc-fsf-trunk-quilt/ports/sysdeps/mips/soft-fp/sfp-machine.h =================================================================== --- glibc-fsf-trunk-quilt.orig/ports/sysdeps/mips/soft-fp/sfp-machine.h 2013-04-23 00:28:50.097012113 +0100 +++ glibc-fsf-trunk-quilt/ports/sysdeps/mips/soft-fp/sfp-machine.h 2013-04-23 00:33:47.108144185 +0100 @@ -14,14 +14,16 @@ #define _FP_DIV_MEAT_D(R,X,Y) _FP_DIV_MEAT_2_udiv(D,R,X,Y) #define _FP_DIV_MEAT_Q(R,X,Y) _FP_DIV_MEAT_4_udiv(Q,R,X,Y) -#define _FP_NANFRAC_S ((_FP_QNANBIT_S << 1) - 1) -#define _FP_NANFRAC_D ((_FP_QNANBIT_D << 1) - 1), -1 -#define _FP_NANFRAC_Q ((_FP_QNANBIT_Q << 1) - 1), -1, -1, -1 +#define _FP_NANFRAC_S (_FP_QNANBIT_S - 1) +#define _FP_NANFRAC_D (_FP_QNANBIT_D - 1), -1 +#define _FP_NANFRAC_Q (_FP_QNANBIT_Q - 1), -1, -1, -1 #define _FP_NANSIGN_S 0 #define _FP_NANSIGN_D 0 #define _FP_NANSIGN_Q 0 #define _FP_KEEPNANFRACP 1 +#define _FP_QNANNEGATEDP 1 + /* From my experiments it seems X is chosen unless one of the NaNs is sNaN, in which case the result is NANSIGN/NANFRAC. */ #define _FP_CHOOSENAN(fs, wc, R, X, Y, OP) \ Index: glibc-fsf-trunk-quilt/ports/sysdeps/powerpc/soft-fp/sfp-machine.h =================================================================== --- glibc-fsf-trunk-quilt.orig/ports/sysdeps/powerpc/soft-fp/sfp-machine.h 2013-04-23 00:28:50.097012113 +0100 +++ glibc-fsf-trunk-quilt/ports/sysdeps/powerpc/soft-fp/sfp-machine.h 2013-04-23 00:33:47.108144185 +0100 @@ -22,6 +22,7 @@ #define _FP_NANSIGN_Q 0 #define _FP_KEEPNANFRACP 1 +#define _FP_QNANNEGATEDP 0 /* Someone please check this. */ #define _FP_CHOOSENAN(fs, wc, R, X, Y, OP) \ Index: glibc-fsf-trunk-quilt/soft-fp/op-common.h =================================================================== --- glibc-fsf-trunk-quilt.orig/soft-fp/op-common.h 2013-04-23 00:33:45.606803329 +0100 +++ glibc-fsf-trunk-quilt/soft-fp/op-common.h 2013-04-23 00:33:47.108144185 +0100 @@ -35,6 +35,16 @@ _FP_I_TYPE X##_e; \ _FP_FRAC_DECL_##wc(X) +/* Test whether the qNaN bit denotes a signaling NaN. */ +#define _FP_FRAC_SNANP(fs, X) \ + ((_FP_QNANNEGATEDP) \ + ? (_FP_FRAC_HIGH_RAW_##fs(X) & _FP_QNANBIT_##fs) \ + : !(_FP_FRAC_HIGH_RAW_##fs(X) & _FP_QNANBIT_##fs)) +#define _FP_FRAC_SNANP_SEMIRAW(fs, X) \ + ((_FP_QNANNEGATEDP) \ + ? (_FP_FRAC_HIGH_##fs(X) & _FP_QNANBIT_SH_##fs) \ + : !(_FP_FRAC_HIGH_##fs(X) & _FP_QNANBIT_SH_##fs)) + /* * Finish truely unpacking a native fp value by classifying the kind * of fp value and normalizing both the exponent and the fraction. @@ -74,7 +84,7 @@ do { \ { \ X##_c = FP_CLS_NAN; \ /* Check for signaling NaN */ \ - if (!(_FP_FRAC_HIGH_RAW_##fs(X) & _FP_QNANBIT_##fs)) \ + if (_FP_FRAC_SNANP(fs, X)) \ FP_SET_EXCEPTION(FP_EX_INVALID); \ } \ break; \ @@ -112,7 +122,7 @@ do { \ do { \ if (X##_e == _FP_EXPMAX_##fs \ && !_FP_FRAC_ZEROP_##wc(X) \ - && !(_FP_FRAC_HIGH_##fs(X) & _FP_QNANBIT_SH_##fs)) \ + && _FP_FRAC_SNANP_SEMIRAW(fs, X)) \ FP_SET_EXCEPTION(FP_EX_INVALID); \ } while (0) @@ -127,6 +137,39 @@ do { \ _FP_FRAC_SLL_##wc(R, _FP_WORKBITS); \ } while (0) +/* Make the fractional part a quiet NaN, preserving the payload + if possible, otherwise make it the canonical quiet NaN and set + the sign bit accordingly. */ +#define _FP_SETQNAN(fs, wc, X) \ +do { \ + if (_FP_QNANNEGATEDP) \ + { \ + _FP_FRAC_HIGH_RAW_##fs(X) &= _FP_QNANBIT_##fs - 1; \ + if (_FP_FRAC_ZEROP_##wc(X)) \ + { \ + X##_s = _FP_NANSIGN_##fs; \ + _FP_FRAC_SET_##wc(X, _FP_NANFRAC_##fs); \ + } \ + } \ + else \ + _FP_FRAC_HIGH_RAW_##fs(X) |= _FP_QNANBIT_##fs; \ +} while (0) +#define _FP_SETQNAN_SEMIRAW(fs, wc, X) \ +do { \ + if (_FP_QNANNEGATEDP) \ + { \ + _FP_FRAC_HIGH_##fs(X) &= _FP_QNANBIT_SH_##fs - 1; \ + if (_FP_FRAC_ZEROP_##wc(X)) \ + { \ + X##_s = _FP_NANSIGN_##fs; \ + _FP_FRAC_SET_##wc(X, _FP_NANFRAC_##fs); \ + _FP_FRAC_SLL_##wc(X, _FP_WORKBITS); \ + } \ + } \ + else \ + _FP_FRAC_HIGH_##fs(X) |= _FP_QNANBIT_SH_##fs; \ +} while (0) + /* Test whether a biased exponent is normal (not zero or maximum). */ #define _FP_EXP_NORMAL(fs, wc, X) (((X##_e + 1) & _FP_EXPMAX_##fs) > 1) @@ -159,7 +202,7 @@ do { \ X##_s = _FP_NANSIGN_##fs; \ } \ else \ - _FP_FRAC_HIGH_RAW_##fs(X) |= _FP_QNANBIT_##fs; \ + _FP_SETQNAN(fs, wc, X); \ } \ } while (0) @@ -273,7 +316,7 @@ do { \ X##_s = _FP_NANSIGN_##fs; \ } \ else \ - _FP_FRAC_HIGH_RAW_##fs(X) |= _FP_QNANBIT_##fs; \ + _FP_SETQNAN(fs, wc, X); \ break; \ } \ } while (0) @@ -287,7 +330,7 @@ do { \ if (X##_e == _FP_EXPMAX_##fs) \ { \ if (!_FP_FRAC_ZEROP_##wc(X) \ - && !(_FP_FRAC_HIGH_RAW_##fs(X) & _FP_QNANBIT_##fs)) \ + && _FP_FRAC_SNANP(fs, X)) \ __ret = 1; \ } \ __ret; \ @@ -1199,7 +1242,7 @@ do { \ D##_e = _FP_EXPMAX_##dfs; \ if (!_FP_FRAC_ZEROP_##swc(S)) \ { \ - if (!(_FP_FRAC_HIGH_RAW_##sfs(S) & _FP_QNANBIT_##sfs)) \ + if (_FP_FRAC_SNANP(sfs, S)) \ FP_SET_EXCEPTION(FP_EX_INVALID); \ _FP_FRAC_SLL_##dwc(D, (_FP_FRACBITS_##dfs \ - _FP_FRACBITS_##sfs)); \ @@ -1286,7 +1329,7 @@ do { \ /* Semi-raw NaN must have all workbits cleared. */ \ _FP_FRAC_LOW_##dwc(D) \ &= ~(_FP_W_TYPE) ((1 << _FP_WORKBITS) - 1); \ - _FP_FRAC_HIGH_##dfs(D) |= _FP_QNANBIT_SH_##dfs; \ + _FP_SETQNAN_SEMIRAW(dfs, dwc, D); \ } \ } \ } \ Index: glibc-fsf-trunk-quilt/soft-fp/testit.c =================================================================== --- glibc-fsf-trunk-quilt.orig/soft-fp/testit.c 2013-04-23 00:28:50.598144385 +0100 +++ glibc-fsf-trunk-quilt/soft-fp/testit.c 2013-04-23 00:33:47.108144185 +0100 @@ -200,17 +200,17 @@ double gen_special_double(int i) case 0: X_c = FP_CLS_NAN; #if _FP_W_TYPE_SIZE < _FP_FRACBITS_D - __FP_FRAC_SET_2(X, _FP_QNANBIT_D, 0x1234); + __FP_FRAC_SET_2(X, _FP_QNANNEGATEDP ? 0 : _FP_QNANBIT_D, 0x1234); #else - _FP_FRAC_SET_1(X, _FP_QNANBIT_D | 0x1234); + _FP_FRAC_SET_1(X, (_FP_QNANNEGATEDP ? 0 : _FP_QNANBIT_D) | 0x1234); #endif break; case 2: X_c = FP_CLS_NAN; #if _FP_W_TYPE_SIZE < _FP_FRACBITS_D - __FP_FRAC_SET_2(X, _FP_QNANBIT_D, 0x1); + __FP_FRAC_SET_2(X, _FP_QNANNEGATEDP ? 0 : _FP_QNANBIT_D, 0x1); #else - _FP_FRAC_SET_1(X, _FP_QNANBIT_D | 0x1); + _FP_FRAC_SET_1(X, (_FP_QNANNEGATEDP ? 0 : _FP_QNANBIT_D) | 0x1); #endif break; case 4: Index: glibc-fsf-trunk-quilt/sysdeps/sparc/sparc32/soft-fp/sfp-machine.h =================================================================== --- glibc-fsf-trunk-quilt.orig/sysdeps/sparc/sparc32/soft-fp/sfp-machine.h 2013-04-23 00:28:50.598144385 +0100 +++ glibc-fsf-trunk-quilt/sysdeps/sparc/sparc32/soft-fp/sfp-machine.h 2013-04-23 00:33:47.108144185 +0100 @@ -47,6 +47,7 @@ #define _FP_NANSIGN_Q 0 #define _FP_KEEPNANFRACP 1 +#define _FP_QNANNEGATEDP 0 /* If one NaN is signaling and the other is not, * we choose that one, otherwise we choose X. Index: glibc-fsf-trunk-quilt/sysdeps/sparc/sparc64/soft-fp/sfp-machine.h =================================================================== --- glibc-fsf-trunk-quilt.orig/sysdeps/sparc/sparc64/soft-fp/sfp-machine.h 2013-04-23 00:28:50.598144385 +0100 +++ glibc-fsf-trunk-quilt/sysdeps/sparc/sparc64/soft-fp/sfp-machine.h 2013-04-23 00:33:47.108144185 +0100 @@ -60,6 +60,7 @@ do { \ #define _FP_NANSIGN_Q 0 #define _FP_KEEPNANFRACP 1 +#define _FP_QNANNEGATEDP 0 /* If one NaN is signaling and the other is not, * we choose that one, otherwise we choose Y.