83 lines
1.3 KiB
C
83 lines
1.3 KiB
C
#include <u.h>
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#include <libc.h>
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#define DEEPS ".5*2^-1073"
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#define DENEPS "-.5*2^-1073"
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#define DEPINF "+Inf*2^0"
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#define DENAN "NaN*2^0"
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jmp_buf errj;
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char *err;
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int fail = 0;
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void
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catcher(void *u, char *s)
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{
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err = 0;
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if(strncmp(s, "sys: fp:", 8) == 0){
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err = s;
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notejmp(u, errj, 0);
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}
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noted(NDFLT);
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}
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void
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decomp(double d, int *exp, char *s)
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{
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double m;
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m = frexp(d, exp);
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fprint(2, "Expected decomposition: %s\n", s);
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fprint(2, "Actual decomposition: %g*2^%d\n", m, *exp);
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if(isNaN(d)){
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if(*exp != 0 || !isNaN(m))
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fail = 1;
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return;
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}
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if(isInf(d, 1)){
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if(*exp != 0 || !isInf(m, 1))
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fail = 1;
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return;
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}
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if(fabs(d - ldexp(m, *exp)) > 4e-16)
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fail = 1;
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}
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void
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main(void)
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{
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double eps, neps;
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int exp;
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err = 0;
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notify(catcher);
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setjmp(errj);
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if(err){
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print("FAIL: %s\n", err);
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exits("FAIL");
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}
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eps = ldexp(1, -1074);
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neps = ldexp(-1, -1074);
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fprint(2, "Smallest Positive Double: %g\n", eps);
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decomp(eps, &exp, DEEPS);
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fprint(2, "Largest Negative Double: %g\n", neps);
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decomp(neps, &exp, DENEPS);
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fprint(2, "Positive infinity: %g\n", Inf(1));
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decomp(Inf(1), &exp, DEPINF);
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fprint(2, "NaN: %g\n", NaN());
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decomp(NaN(), &exp, DENAN);
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if(fail){
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print("FAIL\n");
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exits("FAIL");
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}
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print("PASS\n");
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exits("PASS");
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}
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