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Add a test to prevent regressions. Data is generated using a libFuzzer-based fuzzer and hopefully covers all the important corner cases. Acked-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Message-ID: <20260210214044.1174699-6-iii@linux.ibm.com> Signed-off-by: Thomas Huth <thuth@redhat.com>master
Ilya Leoshkevich
2 months ago
committed by
Thomas Huth
Thomas Huth
2 changed files with 270 additions and 0 deletions
@ -0,0 +1,265 @@ |
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/*
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* Test DIEBR and DIDBR instructions. |
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* |
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* Most inputs were discovered by fuzzing and exercise various corner cases in |
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* the helpers. |
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* |
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* SPDX-License-Identifier: GPL-2.0-or-later |
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*/ |
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#include <signal.h> |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <asm/ucontext.h> |
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static void sigfpe_handler(int sig, siginfo_t *info, void *puc) |
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{ |
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struct ucontext *uc = puc; |
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unsigned short *xr_insn; |
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int r; |
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xr_insn = (unsigned short *)(uc->uc_mcontext.regs.psw.addr - 6); |
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r = *xr_insn & 0xf; |
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uc->uc_mcontext.regs.gprs[r] = sig; |
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} |
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#define DIVIDE_TO_INTEGER(name, floatN) \ |
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static inline __attribute__((__always_inline__)) int \ |
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name(floatN *r1, floatN r2, floatN *r3, int m4, int *sig) \ |
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{ \ |
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int cc; \ |
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\ |
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asm(/* Make the initial CC predictable for suppression tests */ \ |
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"xr %[sig],%[sig]\n" \ |
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#name " %[r1],%[r3],%[r2],%[m4]\n" \ |
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"ipm %[cc]\n" \ |
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"srl %[cc],28" \ |
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/* \
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* Use earlyclobbers to prevent the compiler from reusing floating \ |
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* point registers. This instruction doesn't like it. \ |
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*/ \ |
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: [r1] "+&f" (*r1), [r3] "+&f" (*r3), [sig] "=r" (*sig), [cc] "=d" (cc)\ |
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: [r2] "f" (r2), [m4] "i" (m4) \ |
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: "cc"); \ |
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\ |
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return cc; \ |
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} |
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DIVIDE_TO_INTEGER(diebr, float) |
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DIVIDE_TO_INTEGER(didbr, double) |
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#define TEST_DIVIDE_TO_INTEGER(name, intN, int_fmt, floatN, float_fmt) \ |
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static inline __attribute__((__always_inline__)) int \ |
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test_ ## name(unsigned intN r1i, unsigned intN r2i, int m4, int fpc, \ |
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unsigned intN r1o, unsigned intN r3o, int cco, unsigned int fpco,\ |
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int sigo) \ |
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{ \ |
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union { \ |
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floatN f; \ |
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unsigned intN i; \ |
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} r1, r2, r3; \ |
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int cc, err = 0, sig; \ |
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\ |
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r1.i = r1i; \ |
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r2.i = r2i; \ |
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r3.i = 0x12345678; \ |
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printf("[ RUN ] %" float_fmt "(0x%" int_fmt \ |
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") / %" float_fmt "(0x%" int_fmt ")\n", r1.f, r1.i, r2.f, r2.i); \ |
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asm volatile("sfpc %[fpc]" : : [fpc] "r" (fpc)); \ |
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cc = name(&r1.f, r2.f, &r3.f, m4, &sig); \ |
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asm volatile("stfpc %[fpc]" : [fpc] "=Q" (fpc)); \ |
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if (r1.i != r1o) { \ |
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printf("[ FAILED ] remainder 0x%" int_fmt \ |
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" != expected 0x%" int_fmt "\n", r1.i, r1o); \ |
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err += 1; \ |
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} \ |
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if (r3.i != r3o) { \ |
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printf("[ FAILED ] quotient 0x%" int_fmt \ |
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" != expected 0x%" int_fmt "\n", r3.i, r3o); \ |
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err += 1; \ |
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} \ |
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if (cc != cco) { \ |
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printf("[ FAILED ] cc %d != expected %d\n", cc, cco); \ |
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err += 1; \ |
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} \ |
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if (fpc != fpco) { \ |
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printf("[ FAILED ] fpc 0x%x != expected 0x%x\n", fpc, fpco); \ |
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err += 1; \ |
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} \ |
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if (sig != sigo) { \ |
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printf("[ FAILED ] signal 0x%x != expected 0x%x\n", sig, sigo); \ |
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err += 1; \ |
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} \ |
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\ |
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return err; \ |
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} |
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TEST_DIVIDE_TO_INTEGER(diebr, int, "x", float, "f") |
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TEST_DIVIDE_TO_INTEGER(didbr, long, "lx", double, "lf") |
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int main(void) |
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{ |
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struct sigaction act = { |
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.sa_sigaction = sigfpe_handler, |
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.sa_flags = SA_SIGINFO, |
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}; |
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int err = 0; |
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/* Set up SIG handler */ |
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if (sigaction(SIGFPE, &act, NULL)) { |
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printf("[ FAILED ] sigaction(SIGFPE) failed\n"); |
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return EXIT_FAILURE; |
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} |
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/* 451 / 460 */ |
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err += test_diebr(0x43e1f1f1, 0x43e61616, 7, 0, |
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0x43e1f1f1, 0, 0, 0, 0); |
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/* 480 / 0 */ |
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err += test_diebr(0x43f00000, 0, 0, 0, |
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0x7fc00000, 0x7fc00000, 1, 0x800000, 0); |
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/* QNaN / QNaN */ |
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err += test_diebr(0xffffffff, 0xffffffff, 0, 0, |
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0xffffffff, 0xffffffff, 1, 0, 0); |
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/* -2.08E-8 / -2.08E-8 */ |
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err += test_diebr(0xb2b2b2b2, 0xb2b2b2b2, 0, 0, |
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0x80000000, 0x3f800000, 0, 0, 0); |
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/*
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* Test partial remainder without quotient scaling (cc2). |
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* |
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* a = 12401981 / 268435456 |
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* b = -5723991 / 72057594037927936 |
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* q = a / b = -3329131425038336 / 5723991 =~ -581610178.1 |
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* n = round(q, float32, nearest_even) = -581610176 |
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* r_precise = a - b * n = 189155 / 1125899906842624 |
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* r = round(r_precise, float32, nearest_even) = r_precise |
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*/ |
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err += test_diebr(0x3d3d3d3d, 0xaeaeaeae, 0, 0, |
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0x2f38b8c0, 0xce0aaaab, 2, 0, 0); |
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/* 1.07E-31 / 2.19 */ |
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err += test_diebr(0x0c0c0c0c, 0x400c0c0c, 6, 0, |
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0xc00c0c0c, 0x3f800000, 0, 0x80000, 0); |
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/*
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* Test partial remainder with quotient scaling (cc3). |
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* |
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* a = 298343530578310714772108083200 |
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* b = -592137/10384593717069655257060992658440192 |
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* q = a / b |
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* = -1032725451057301340137043014721780674141077289604872315653324800 / |
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* 197379 |
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* =~ -5232195173029052432817285601415452880707052369324357280426.6 |
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* n = round(q, float32, nearest_even) |
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* = -5232194943010009439437691768433469154159343131709361094656 |
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* n / 2^192 = -6992213 / 8388608 |
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* r_precise = a - b * n = 13115851209189604982784 |
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* r = round(r_precise, float32, nearest_even) = r_precise |
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*/ |
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err += test_diebr(0x7070ffff, 0x90909090, 0, 0, |
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0x6431c0c0, 0xbf5562aa, 3, 0, 0); |
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/*
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* Test large, but representable quotient. |
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* |
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* a = -12040119 / 549755813888 |
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* b = 1 / 38685626227668133590597632 |
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* q = a / b = -847248053779631702016 |
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* n = round(q, float32, to_odd) = q |
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* r_precise = a - b * n = -0 |
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* r = round(r_precise, float32, nearest_even) = -0 |
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*/ |
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err += test_diebr(0xb7b7b7b7, 0x15000000, 7, 0, |
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0x80000000, 0xe237b7b7, 0, 0, 0); |
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/* 0 / 0 */ |
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err += test_diebr(0, 0, 1, 0, |
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0x7fc00000, 0x7fc00000, 1, 0x800000, 0); |
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/* 4.3E-33 / -2.08E-8 with SIGFPE */ |
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err += test_diebr(0x09b2b2b2, 0xb2b2b2b2, 0, 0xfc000007, |
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0xb2b2b2b1, 0xbf800000, 0, 0xfc000807, SIGFPE); |
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/*
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* Test tiny remainder scaling when FPC Underflow Mask is set. |
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* |
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* 1.19E-39 / -1.28E-9 = { r = 1.19E-39 * 2^192, n = -0 } |
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*/ |
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err += test_diebr(0x000d0100, 0xb0b0b0b0, 6, 0xfc000000, |
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0x5ed01000, 0x80000000, 0, 0xfc001000, SIGFPE); |
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/*
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* Test "inexact and incremented" DXC. |
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* |
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* a = 53555504 |
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* b = -520849213389117849600 |
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* q = a / b = -3347219 / 32553075836819865600 |
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* n = round(q, float32, to_odd) = -1 |
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* r_precise = a - b * n = -520849213389064294096 |
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* r = round(r_precise, float32, to_odd) = -520849213389117849600 |
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* abs(r) - abs(r_precise) = 53555504 |
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*/ |
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err += test_diebr(0x4c4c4c4c, 0xe1e1e1e1, 0, 0xfc000007, |
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0xe1e1e1e1, 0xbf800000, 0, 0xfc000c07, SIGFPE); |
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/* 0 / 0 with SIGFPE */ |
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err += test_diebr(0, 0, 0, 0xfc000007, |
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0, 0x12345678, 0, 0xfc008007, SIGFPE); |
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/* 5.76E-16 / 5.39E+34 */ |
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err += test_diebr(0x26262626, 0x79262626, 6, 0, |
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0xf9262626, 0x3f800000, 0, 0x80000, 0); |
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/* -4.97E+17 / 2.03E-38 */ |
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err += test_diebr(0xdcdcdcdc, 0x00dcdcdc, 7, 0xfc000000, |
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0x80000000, 0xbb800000, 1, 0xfc000000, 0); |
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/* -1.23E+17 / SNaN */ |
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err += test_diebr(0xdbdb240b, 0xffac73ff, 4, 0, |
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0xffec73ff, 0xffec73ff, 1, 0x800000, 0); |
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/* 2.34E-38 / 3.27E-33 with SIGFPE */ |
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err += test_diebr(0x00ff0987, 0x0987c6f6, 6, 0x08000000, |
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0x8987c6b6, 0x3f800000, 0, 0x8000800, SIGFPE); |
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/* -5.93E+11 / -2.7E+4 */ |
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err += test_diebr(0xd30a0040, 0xc6d30a00, 0, 0xc4000000, |
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0xc74a4400, 0x4ba766c6, 2, 0xc4000000, 0); |
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/* 9.86E-32 / -inf */ |
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err += test_diebr(0x0c000029, 0xff800000, 0, 0, |
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0xc000029, 0x80000000, 0, 0, 0); |
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/* QNaN / SNaN */ |
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err += test_diebr(0xffff94ff, 0xff94ff24, 4, 7, |
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0xffd4ff24, 0xffd4ff24, 1, 0x800007, 0); |
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/* 2.8E-43 / -inf */ |
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err += test_diebr(0x000000c8, 0xff800000, 0, 0x7c000007, |
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0x000000c8, 0x80000000, 0, 0x7c000007, 0); |
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/* -1.7E+38 / -inf */ |
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err += test_diebr(0xff00003d, 0xff800000, 0, 0, |
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0xff00003d, 0, 0, 0, 0); |
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/* 1.94E-304 / 1.94E-304 */ |
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err += test_didbr(0x00e100e100e100e1, 0x00e100e100e100e1, 0, 1, |
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0, 0x3ff0000000000000, 0, 1, 0); |
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/* 4.82E-299 / 5.29E-308 */ |
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err += test_didbr(0x0200230200230200, 0x0023020023020023, 0, 0, |
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0x8001a017d247b3f4, 0x41cb2aa05f000000, 0, 0, 0); |
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/* -1.38E-75 / -3.77E+208 */ |
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err += test_didbr(0xb063eb3d63b063eb, 0xeb3d63b063eb3d63, 3, 0xe8000000, |
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0x6b3d63b063eb3d63, 0x3ff0000000000000, 0, 0xe8000c00, |
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SIGFPE); |
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/* 4.78E-299 / 6.88E-315 */ |
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err += test_didbr(0x0200000000000000, 0x0000000053020000, 0, 0, |
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0x8000000020820000, 0x4338ac20dd47c6c1, 0, 0, 0); |
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return err ? EXIT_FAILURE : EXIT_SUCCESS; |
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} |
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