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Diffstat (limited to 'gdtoa/arithchk.c')
| -rw-r--r-- | gdtoa/arithchk.c | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/gdtoa/arithchk.c b/gdtoa/arithchk.c new file mode 100644 index 00000000..3211aeda --- /dev/null +++ b/gdtoa/arithchk.c @@ -0,0 +1,183 @@ +/**************************************************************** +Copyright (C) 1997, 1998 Lucent Technologies +All Rights Reserved + +Permission to use, copy, modify, and distribute this software and +its documentation for any purpose and without fee is hereby +granted, provided that the above copyright notice appear in all +copies and that both that the copyright notice and this +permission notice and warranty disclaimer appear in supporting +documentation, and that the name of Lucent or any of its entities +not be used in advertising or publicity pertaining to +distribution of the software without specific, written prior +permission. + +LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, +INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. +IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY +SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES +WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER +IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, +ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF +THIS SOFTWARE. +****************************************************************/ + +/* Try to deduce arith.h from arithmetic properties. */ + +#include <stdio.h> + + static int dalign; + typedef struct +Akind { + char *name; + int kind; + } Akind; + + static Akind +IEEE_8087 = { "IEEE_8087", 1 }, +IEEE_MC68k = { "IEEE_MC68k", 2 }, +IBM = { "IBM", 3 }, +VAX = { "VAX", 4 }, +CRAY = { "CRAY", 5}; + + static Akind * +Lcheck() +{ + union { + double d; + long L[2]; + } u; + struct { + double d; + long L; + } x[2]; + + if (sizeof(x) > 2*(sizeof(double) + sizeof(long))) + dalign = 1; + u.L[0] = u.L[1] = 0; + u.d = 1e13; + if (u.L[0] == 1117925532 && u.L[1] == -448790528) + return &IEEE_MC68k; + if (u.L[1] == 1117925532 && u.L[0] == -448790528) + return &IEEE_8087; + if (u.L[0] == -2065213935 && u.L[1] == 10752) + return &VAX; + if (u.L[0] == 1267827943 && u.L[1] == 704643072) + return &IBM; + return 0; + } + + static Akind * +icheck() +{ + union { + double d; + int L[2]; + } u; + struct { + double d; + int L; + } x[2]; + + if (sizeof(x) > 2*(sizeof(double) + sizeof(int))) + dalign = 1; + u.L[0] = u.L[1] = 0; + u.d = 1e13; + if (u.L[0] == 1117925532 && u.L[1] == -448790528) + return &IEEE_MC68k; + if (u.L[1] == 1117925532 && u.L[0] == -448790528) + return &IEEE_8087; + if (u.L[0] == -2065213935 && u.L[1] == 10752) + return &VAX; + if (u.L[0] == 1267827943 && u.L[1] == 704643072) + return &IBM; + return 0; + } + +char *emptyfmt = ""; /* avoid possible warning message with printf("") */ + + static Akind * +ccheck() +{ + union { + double d; + long L; + } u; + long Cray1; + + /* Cray1 = 4617762693716115456 -- without overflow on non-Crays */ + Cray1 = printf(emptyfmt) < 0 ? 0 : 4617762; + if (printf(emptyfmt, Cray1) >= 0) + Cray1 = 1000000*Cray1 + 693716; + if (printf(emptyfmt, Cray1) >= 0) + Cray1 = 1000000*Cray1 + 115456; + u.d = 1e13; + if (u.L == Cray1) + return &CRAY; + return 0; + } + + static int +fzcheck() +{ + double a, b; + int i; + + a = 1.; + b = .1; + for(i = 155;; b *= b, i >>= 1) { + if (i & 1) { + a *= b; + if (i == 1) + break; + } + } + b = a * a; + return b == 0.; + } + + int +main() +{ + Akind *a = 0; + int Ldef = 0; + FILE *f; + +#ifdef WRITE_ARITH_H /* for Symantec's buggy "make" */ + f = fopen("arith.h", "w"); + if (!f) { + printf("Cannot open arith.h\n"); + return 1; + } +#else + f = stdout; +#endif + + if (sizeof(double) == 2*sizeof(long)) + a = Lcheck(); + else if (sizeof(double) == 2*sizeof(int)) { + Ldef = 1; + a = icheck(); + } + else if (sizeof(double) == sizeof(long)) + a = ccheck(); + if (a) { + fprintf(f, "#define %s\n#define Arith_Kind_ASL %d\n", + a->name, a->kind); + if (Ldef) + fprintf(f, "#define Long int\n#define Intcast (int)(long)\n"); + if (dalign) + fprintf(f, "#define Double_Align\n"); + if (sizeof(char*) == 8) + fprintf(f, "#define X64_bit_pointers\n"); +#ifndef NO_LONG_LONG + if (sizeof(long long) < 8) +#endif + fprintf(f, "#define NO_LONG_LONG\n"); + if (a->kind <= 2 && fzcheck()) + fprintf(f, "#define Sudden_Underflow\n"); + return 0; + } + fprintf(f, "/* Unknown arithmetic */\n"); + return 1; + } |