mirror of
https://git.busybox.net/uClibc
synced 2025-05-09 23:31:39 +08:00
5d53cce4c0
update example libc/sysdeps/linux/i386/bits/mathinline.h: improve __finite() macro, add __finitef macro (why they aren't always macros? why aren't they arch independent?) libm/math_private.h: much better comments on math_opt_barrier() and math_force_eval() libm/s_finite[f].c: improve out-of-line __finite[f]() too (one byte less, yay...)
65 lines
1.4 KiB
C
65 lines
1.4 KiB
C
/* Small test program for probing how various math functions
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* with specific operands set floating point exceptions
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*/
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#define _ISOC99_SOURCE 1
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#define _GNU_SOURCE 1
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#include <stdint.h>
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#include <math.h>
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#include <fenv.h>
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#include <stdio.h>
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int main(int argc, char **argv)
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{
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float largest, small, t, inf_float;
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largest = small = 1;
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while (1) {
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t = largest + small;
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/* optimizations may make plain "t == largest" unreliable */
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if (memcmp(&t, &largest, sizeof(float)) == 0)
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break;
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if (isfinite(t)) {
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largest = t;
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small *= 2;
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continue;
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}
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small /= 2;
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}
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inf_float = largest + largest;
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//printf("%.40g ", largest);
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//printf("[%llx]\n", (long long) (*(uint32_t *)&largest));
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feclearexcept(FE_ALL_EXCEPT);
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//t = 1.0 / 0.0; // simple test: FE_DIVBYZERO
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//t = nextafterf(largest, 1); // glibc 2.8: no math exceptions raised
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//t = nextafterf(largest, largest); // glibc 2.8: no math exceptions raised
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//t = nextafterf(largest, inf_float); // glibc 2.8: FE_INEXACT FE_OVERFLOW
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#define PREX(ex) do { if (fetestexcept(ex)) printf(#ex " "); } while(0)
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#ifdef FE_INEXACT
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PREX(FE_INEXACT);
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#endif
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#ifdef FE_DIVBYZERO
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PREX(FE_DIVBYZERO);
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#endif
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#ifdef FE_UNDERFLOW
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PREX(FE_UNDERFLOW);
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#endif
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#ifdef FE_OVERFLOW
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PREX(FE_OVERFLOW);
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#endif
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#ifdef FE_INVALID
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PREX(FE_INVALID);
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#endif
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if (fetestexcept(FE_ALL_EXCEPT))
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printf("\n");
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else
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printf("no math exceptions raised\n");
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printf("%.40g\n", t);
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return 0;
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}
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