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qemu/tests/tcg/test-i386-fprem.c

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/*
* x86 FPREM test - executes the FPREM and FPREM1 instructions with corner case
* operands and prints the operands, result and FPU status word.
*
* Run this on real hardware, then under QEMU, and diff the outputs, to compare
* QEMU's implementation to your hardware. The 'run-test-i386-fprem' make
* target does this.
*
* Copyright (c) 2003 Fabrice Bellard
* Copyright (c) 2012 Catalin Patulea
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/compiler.h"
#include "qemu/osdep.h"
#include <stdio.h>
#include <inttypes.h>
/*
* Inspired by <ieee754.h>'s union ieee854_long_double, but with single
* long long mantissa fields and assuming little-endianness for simplicity.
*/
union float80u {
long double d;
/* This is the IEEE 854 double-extended-precision format. */
struct {
unsigned long long mantissa:63;
unsigned int one:1;
unsigned int exponent:15;
unsigned int negative:1;
unsigned int empty:16;
} QEMU_PACKED ieee;
/* This is for NaNs in the IEEE 854 double-extended-precision format. */
struct {
unsigned long long mantissa:62;
unsigned int quiet_nan:1;
unsigned int one:1;
unsigned int exponent:15;
unsigned int negative:1;
unsigned int empty:16;
} QEMU_PACKED ieee_nan;
};
#define IEEE854_LONG_DOUBLE_BIAS 0x3fff
static const union float80u q_nan = {
.ieee_nan.negative = 0, /* X */
.ieee_nan.exponent = 0x7fff,
.ieee_nan.one = 1,
.ieee_nan.quiet_nan = 1,
.ieee_nan.mantissa = 0,
};
static const union float80u s_nan = {
.ieee_nan.negative = 0, /* X */
.ieee_nan.exponent = 0x7fff,
.ieee_nan.one = 1,
.ieee_nan.quiet_nan = 0,
.ieee_nan.mantissa = 1, /* nonzero */
};
static const union float80u pos_inf = {
.ieee.negative = 0,
.ieee.exponent = 0x7fff,
.ieee.one = 1,
.ieee.mantissa = 0,
};
static const union float80u pseudo_pos_inf = { /* "unsupported" */
.ieee.negative = 0,
.ieee.exponent = 0x7fff,
.ieee.one = 0,
.ieee.mantissa = 0,
};
static const union float80u pos_denorm = {
.ieee.negative = 0,
.ieee.exponent = 0,
.ieee.one = 0,
.ieee.mantissa = 1,
};
static const union float80u smallest_positive_norm = {
.ieee.negative = 0,
.ieee.exponent = 1,
.ieee.one = 1,
.ieee.mantissa = 0,
};
static void fninit()
{
asm volatile ("fninit\n");
}
static long double fprem(long double a, long double b, uint16_t *sw)
{
long double result;
asm volatile ("fprem\n"
"fnstsw %1\n"
: "=t" (result), "=m" (*sw)
: "0" (a), "u" (b)
: "st(1)");
return result;
}
static long double fprem1(long double a, long double b, uint16_t *sw)
{
long double result;
asm volatile ("fprem1\n"
"fnstsw %1\n"
: "=t" (result), "=m" (*sw)
: "0" (a), "u" (b)
: "st(1)");
return result;
}
#define FPUS_IE (1 << 0)
#define FPUS_DE (1 << 1)
#define FPUS_ZE (1 << 2)
#define FPUS_OE (1 << 3)
#define FPUS_UE (1 << 4)
#define FPUS_PE (1 << 5)
#define FPUS_SF (1 << 6)
#define FPUS_SE (1 << 7)
#define FPUS_C0 (1 << 8)
#define FPUS_C1 (1 << 9)
#define FPUS_C2 (1 << 10)
#define FPUS_TOP 0x3800
#define FPUS_C3 (1 << 14)
#define FPUS_B (1 << 15)
#define FPUS_EMASK 0x007f
#define FPUC_EM 0x3f
static void psw(uint16_t sw)
{
printf("SW: C3 TopC2C1C0\n");
printf("SW: %c %d %3d %d %d %d %c %c %c %c %c %c %c %c\n",
sw & FPUS_B ? 'B' : 'b',
!!(sw & FPUS_C3),
(sw & FPUS_TOP) >> 11,
!!(sw & FPUS_C2),
!!(sw & FPUS_C1),
!!(sw & FPUS_C0),
(sw & FPUS_SE) ? 'S' : 's',
(sw & FPUS_SF) ? 'F' : 'f',
(sw & FPUS_PE) ? 'P' : 'p',
(sw & FPUS_UE) ? 'U' : 'u',
(sw & FPUS_OE) ? 'O' : 'o',
(sw & FPUS_ZE) ? 'Z' : 'z',
(sw & FPUS_DE) ? 'D' : 'd',
(sw & FPUS_IE) ? 'I' : 'i');
}
static void do_fprem(long double a, long double b)
{
const union float80u au = {.d = a};
const union float80u bu = {.d = b};
union float80u ru;
uint16_t sw;
printf("A: S=%d Exp=%04x Int=%d (QNaN=%d) Sig=%016llx (%.06Le)\n",
au.ieee.negative, au.ieee.exponent, au.ieee.one,
au.ieee_nan.quiet_nan, (unsigned long long)au.ieee.mantissa,
a);
printf("B: S=%d Exp=%04x Int=%d (QNaN=%d) Sig=%016llx (%.06Le)\n",
bu.ieee.negative, bu.ieee.exponent, bu.ieee.one,
bu.ieee_nan.quiet_nan, (unsigned long long)bu.ieee.mantissa,
b);
fflush(stdout);
fninit();
ru.d = fprem(a, b, &sw);
psw(sw);
printf("R : S=%d Exp=%04x Int=%d (QNaN=%d) Sig=%016llx (%.06Le)\n",
ru.ieee.negative, ru.ieee.exponent, ru.ieee.one,
ru.ieee_nan.quiet_nan, (unsigned long long)ru.ieee.mantissa,
ru.d);
fninit();
ru.d = fprem1(a, b, &sw);
psw(sw);
printf("R1: S=%d Exp=%04x Int=%d (QNaN=%d) Sig=%016llx (%.06Le)\n",
ru.ieee.negative, ru.ieee.exponent, ru.ieee.one,
ru.ieee_nan.quiet_nan, (unsigned long long)ru.ieee.mantissa,
ru.d);
printf("\n");
}
static void do_fprem_stack_underflow(void)
{
const long double a = 1.0;
union float80u ru;
uint16_t sw;
fninit();
asm volatile ("fprem\n"
"fnstsw %1\n"
: "=t" (ru.d), "=m" (sw)
: "0" (a)
: "st(1)");
psw(sw);
printf("R: S=%d Exp=%04x Int=%d (QNaN=%d) Sig=%016llx (%.06Le)\n",
ru.ieee.negative, ru.ieee.exponent, ru.ieee.one,
ru.ieee_nan.quiet_nan, (unsigned long long)ru.ieee.mantissa,
ru.d);
printf("\n");
}
static void test_fprem_cases(void)
{
printf("= stack underflow =\n");
do_fprem_stack_underflow();
printf("= invalid operation =\n");
do_fprem(s_nan.d, 1.0);
do_fprem(1.0, 0.0);
do_fprem(pos_inf.d, 1.0);
do_fprem(pseudo_pos_inf.d, 1.0);
printf("= denormal =\n");
do_fprem(pos_denorm.d, 1.0);
do_fprem(1.0, pos_denorm.d);
/* printf("= underflow =\n"); */
/* TODO: Is there a case where FPREM raises underflow? */
}
static void test_fprem_pairs(void)
{
unsigned long long count;
unsigned int negative_index_a = 0;
unsigned int negative_index_b = 0;
static const unsigned int negative_values[] = {
0,
1,
};
unsigned int exponent_index_a = 0;
unsigned int exponent_index_b = 0;
static const unsigned int exponent_values[] = {
0,
1,
2,
IEEE854_LONG_DOUBLE_BIAS - 1,
IEEE854_LONG_DOUBLE_BIAS,
IEEE854_LONG_DOUBLE_BIAS + 1,
0x7ffd,
0x7ffe,
0x7fff,
};
unsigned int one_index_a = 0;
unsigned int one_index_b = 0;
static const unsigned int one_values[] = {
0,
1,
};
unsigned int quiet_nan_index_a = 0;
unsigned int quiet_nan_index_b = 0;
static const unsigned int quiet_nan_values[] = {
0,
1,
};
unsigned int mantissa_index_a = 0;
unsigned int mantissa_index_b = 0;
static const unsigned long long mantissa_values[] = {
0,
1,
2,
0x3ffffffffffffffdULL,
0x3ffffffffffffffeULL,
0x3fffffffffffffffULL,
};
for (count = 0; ; ++count) {
#define INIT_FIELD(var, field) \
.ieee_nan.field = field##_values[field##_index_##var]
const union float80u a = {
INIT_FIELD(a, negative),
INIT_FIELD(a, exponent),
INIT_FIELD(a, one),
INIT_FIELD(a, quiet_nan),
INIT_FIELD(a, mantissa),
};
const union float80u b = {
INIT_FIELD(b, negative),
INIT_FIELD(b, exponent),
INIT_FIELD(b, one),
INIT_FIELD(b, quiet_nan),
INIT_FIELD(b, mantissa),
};
#undef INIT_FIELD
do_fprem(a.d, b.d);
int carry = 1;
#define CARRY_INTO(var, field) do { \
if (carry) { \
if (++field##_index_##var == ARRAY_SIZE(field##_values)) { \
field##_index_##var = 0; \
} else { \
carry = 0; \
} \
} \
} while (0)
CARRY_INTO(b, mantissa);
CARRY_INTO(b, quiet_nan);
CARRY_INTO(b, one);
CARRY_INTO(b, exponent);
CARRY_INTO(b, negative);
CARRY_INTO(a, mantissa);
CARRY_INTO(a, quiet_nan);
CARRY_INTO(a, one);
CARRY_INTO(a, exponent);
CARRY_INTO(a, negative);
#undef CARRY_INTO
if (carry) {
break;
}
}
fprintf(stderr, "test-i386-fprem: tested %llu cases\n", count);
}
int main(int argc, char **argv)
{
test_fprem_cases();
test_fprem_pairs();
return 0;
}
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