137 lines
6.1 KiB
C
137 lines
6.1 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ This program is free software; you can redistribute it and/or modify │
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│ it under the terms of the GNU General Public License as published by │
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│ the Free Software Foundation; version 2 of the License. │
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│ │
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│ This program is distributed in the hope that it will be useful, but │
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│ WITHOUT ANY WARRANTY; without even the implied warranty of │
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│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
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│ General Public License for more details. │
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│ │
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│ You should have received a copy of the GNU General Public License │
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│ along with this program; if not, write to the Free Software │
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│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
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│ 02110-1301 USA │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/math.h"
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#include "libc/runtime/gc.h"
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#include "libc/stdio/stdio.h"
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#include "libc/str/str.h"
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#include "libc/x/x.h"
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#include "third_party/gdtoa/gdtoa.h"
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const char kConfig[] = "\
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/* FPU Control Word (x87) Exception Masks\n\
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@see Intel Manual V1 §8.1.5\n\
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IM: Invalid Operation ───────────────┐\n\
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DM: Denormal Operand ───────────────┐│\n\
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ZM: Zero Divide ───────────────────┐││\n\
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OM: Overflow ─────────────────────┐│││\n\
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UM: Underflow ───────────────────┐││││\n\
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PM: Precision ──────────────────┐│││││\n\
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PC: Precision Control ────────┐ ││││││\n\
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{float,∅,double,long double} │ ││││││\n\
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RC: Rounding Control ───────┐ │ ││││││\n\
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{even, →-∞, →+∞, →0} │┌┤ ││││││\n\
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┌┤││ ││││││\n\
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d││││rr││││││*/\n\
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";
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const char kStatus[] = "\
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/* FPU Status Word (x87)\n\
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@see Intel Manual V1 §8.1.3\n\
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IE: Invalid Operation ────────────────┐\n\
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DE: Denormalized Operand ────────────┐│\n\
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ZE: Zero Divide ────────────────────┐││\n\
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OE: Overflow Flag ─────────────────┐│││\n\
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UE: Underflow Flag ───────────────┐││││\n\
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PE: Precision Flag ──────────────┐│││││\n\
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SF: Stack Fault ────────────────┐││││││\n\
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ES: Exception Summary Status ──┐│││││││\n\
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C0-3: Condition Codes ──┬────┐ ││││││││\n\
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TOP of Stack Pointer ─────┐ │ ││││││││\n\
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B: FPU Busy ───────────┐│ │ │ ││││││││\n\
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││┌┴┐┌┼┐││││││││\n\
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│↓│ │↓↓↓││││││││*/\n\
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";
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const char kRegister[] = "\
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/\t┌sign\n\
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/\t│ ┌exponent\n\
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/\t│ │ ┌intpart\n\
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/\t│ │ │ ┌fraction\n\
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/\t│ │ │ │\n\
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/\t│┌┴────────────┐│┌┴────────────────────────────────────────────────────────────┐\n";
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void PrintRegister(long double x) {
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char buf[32];
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uint16_t lo, hi;
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memcpy(buf, &x, sizeof(x));
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memcpy(&lo, &buf[0], sizeof(lo));
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memcpy(&hi, &buf[8], sizeof(hi));
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g_xfmt_p(buf, &x, 15, 32, 0);
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printf("/\t%016lb%064lb %s\n", hi, lo, buf);
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}
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int main(int argc, char *argv[]) {
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double d;
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unsigned short sw;
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long double st0, st1;
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#define ST0 1
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#define ST1 2
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d = 0;
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st0 = ST0;
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st1 = ST1;
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asm("fstl\t%1\n\t"
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"fstsw"
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: "=a"(sw), "=m"(d) /*, "+t"(st0), "+u"(st1) */);
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printf("\n%s%016b\n\n%s", kStatus, sw, kRegister);
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PrintRegister(st0);
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PrintRegister(st1);
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printf("/\t%-80s %s\n", "d", gc(xdtoa(d)));
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#if 0
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#define ST0 2e18L
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#define ST1 0.0000000000000123L
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st0 = ST0;
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st1 = ST1;
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asm("fldpi\n\t"
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"fadd\t%%st\n\t"
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"fxch\n2:\t"
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"fprem1\n\t"
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"fnstsw\n\t"
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"test\t$4,%%ah\n\t"
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"jnz\t2b\n\t"
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"fstp\t%%st(1)\n\t"
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"fsin\n\t"
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"fstsw"
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: "=a"(sw), "+t"(st0), "+u"(st1));
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printf("\n%s%016b\n\n%s", kStatus, sw, kRegister);
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PrintRegister(st0);
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PrintRegister(st1);
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#endif
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#if 0
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st0 = ST0;
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st1 = ST1;
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asm("fsin\n\t"
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"fstsw"
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: "=a"(sw), "+t"(st0), "+u"(st1));
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printf("\n%s%016b\n\n%s", kStatus, sw, kRegister);
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PrintRegister(st0);
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PrintRegister(st1);
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#endif
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#if 0
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printf("\n");
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PrintRegister(sinl(remainderl(2e40L, M_PI * 2)));
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#endif
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return 0;
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}
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