qemu-e2k/target-s390x/fpu_helper.c

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/*
* S/390 FPU helper routines
*
* Copyright (c) 2009 Ulrich Hecht
* Copyright (c) 2009 Alexander Graf
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#include "cpu.h"
#include "exec/cpu_ldst.h"
#include "exec/helper-proto.h"
/* #define DEBUG_HELPER */
#ifdef DEBUG_HELPER
#define HELPER_LOG(x...) qemu_log(x)
#else
#define HELPER_LOG(x...)
#endif
#define RET128(F) (env->retxl = F.low, F.high)
#define convert_bit(mask, from, to) \
(to < from \
? (mask / (from / to)) & to \
: (mask & from) * (to / from))
static void ieee_exception(CPUS390XState *env, uint32_t dxc, uintptr_t retaddr)
{
/* Install the DXC code. */
env->fpc = (env->fpc & ~0xff00) | (dxc << 8);
/* Trap. */
runtime_exception(env, PGM_DATA, retaddr);
}
/* Should be called after any operation that may raise IEEE exceptions. */
static void handle_exceptions(CPUS390XState *env, uintptr_t retaddr)
{
unsigned s390_exc, qemu_exc;
/* Get the exceptions raised by the current operation. Reset the
fpu_status contents so that the next operation has a clean slate. */
qemu_exc = env->fpu_status.float_exception_flags;
if (qemu_exc == 0) {
return;
}
env->fpu_status.float_exception_flags = 0;
/* Convert softfloat exception bits to s390 exception bits. */
s390_exc = 0;
s390_exc |= convert_bit(qemu_exc, float_flag_invalid, 0x80);
s390_exc |= convert_bit(qemu_exc, float_flag_divbyzero, 0x40);
s390_exc |= convert_bit(qemu_exc, float_flag_overflow, 0x20);
s390_exc |= convert_bit(qemu_exc, float_flag_underflow, 0x10);
s390_exc |= convert_bit(qemu_exc, float_flag_inexact, 0x08);
/* Install the exceptions that we raised. */
env->fpc |= s390_exc << 16;
/* Send signals for enabled exceptions. */
s390_exc &= env->fpc >> 24;
if (s390_exc) {
ieee_exception(env, s390_exc, retaddr);
}
}
static inline int float_comp_to_cc(CPUS390XState *env, int float_compare)
{
S390CPU *cpu = s390_env_get_cpu(env);
switch (float_compare) {
case float_relation_equal:
return 0;
case float_relation_less:
return 1;
case float_relation_greater:
return 2;
case float_relation_unordered:
return 3;
default:
cpu_abort(CPU(cpu), "unknown return value for float compare\n");
}
}
/* condition codes for unary FP ops */
uint32_t set_cc_nz_f32(float32 v)
{
if (float32_is_any_nan(v)) {
return 3;
} else if (float32_is_zero(v)) {
return 0;
} else if (float32_is_neg(v)) {
return 1;
} else {
return 2;
}
}
uint32_t set_cc_nz_f64(float64 v)
{
if (float64_is_any_nan(v)) {
return 3;
} else if (float64_is_zero(v)) {
return 0;
} else if (float64_is_neg(v)) {
return 1;
} else {
return 2;
}
}
uint32_t set_cc_nz_f128(float128 v)
{
if (float128_is_any_nan(v)) {
return 3;
} else if (float128_is_zero(v)) {
return 0;
} else if (float128_is_neg(v)) {
return 1;
} else {
return 2;
}
}
/* 32-bit FP addition */
uint64_t HELPER(aeb)(CPUS390XState *env, uint64_t f1, uint64_t f2)
{
float32 ret = float32_add(f1, f2, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* 64-bit FP addition */
uint64_t HELPER(adb)(CPUS390XState *env, uint64_t f1, uint64_t f2)
{
float64 ret = float64_add(f1, f2, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* 128-bit FP addition */
uint64_t HELPER(axb)(CPUS390XState *env, uint64_t ah, uint64_t al,
uint64_t bh, uint64_t bl)
{
float128 ret = float128_add(make_float128(ah, al),
make_float128(bh, bl),
&env->fpu_status);
handle_exceptions(env, GETPC());
return RET128(ret);
}
/* 32-bit FP subtraction */
uint64_t HELPER(seb)(CPUS390XState *env, uint64_t f1, uint64_t f2)
{
float32 ret = float32_sub(f1, f2, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* 64-bit FP subtraction */
uint64_t HELPER(sdb)(CPUS390XState *env, uint64_t f1, uint64_t f2)
{
float64 ret = float64_sub(f1, f2, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* 128-bit FP subtraction */
uint64_t HELPER(sxb)(CPUS390XState *env, uint64_t ah, uint64_t al,
uint64_t bh, uint64_t bl)
{
float128 ret = float128_sub(make_float128(ah, al),
make_float128(bh, bl),
&env->fpu_status);
handle_exceptions(env, GETPC());
return RET128(ret);
}
/* 32-bit FP division */
uint64_t HELPER(deb)(CPUS390XState *env, uint64_t f1, uint64_t f2)
{
float32 ret = float32_div(f1, f2, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* 64-bit FP division */
uint64_t HELPER(ddb)(CPUS390XState *env, uint64_t f1, uint64_t f2)
{
float64 ret = float64_div(f1, f2, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* 128-bit FP division */
uint64_t HELPER(dxb)(CPUS390XState *env, uint64_t ah, uint64_t al,
uint64_t bh, uint64_t bl)
{
float128 ret = float128_div(make_float128(ah, al),
make_float128(bh, bl),
&env->fpu_status);
handle_exceptions(env, GETPC());
return RET128(ret);
}
/* 32-bit FP multiplication */
uint64_t HELPER(meeb)(CPUS390XState *env, uint64_t f1, uint64_t f2)
{
float32 ret = float32_mul(f1, f2, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* 64-bit FP multiplication */
uint64_t HELPER(mdb)(CPUS390XState *env, uint64_t f1, uint64_t f2)
{
float64 ret = float64_mul(f1, f2, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* 64/32-bit FP multiplication */
uint64_t HELPER(mdeb)(CPUS390XState *env, uint64_t f1, uint64_t f2)
{
float64 ret = float32_to_float64(f2, &env->fpu_status);
ret = float64_mul(f1, ret, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* 128-bit FP multiplication */
uint64_t HELPER(mxb)(CPUS390XState *env, uint64_t ah, uint64_t al,
uint64_t bh, uint64_t bl)
{
float128 ret = float128_mul(make_float128(ah, al),
make_float128(bh, bl),
&env->fpu_status);
handle_exceptions(env, GETPC());
return RET128(ret);
}
/* 128/64-bit FP multiplication */
uint64_t HELPER(mxdb)(CPUS390XState *env, uint64_t ah, uint64_t al,
uint64_t f2)
{
float128 ret = float64_to_float128(f2, &env->fpu_status);
ret = float128_mul(make_float128(ah, al), ret, &env->fpu_status);
handle_exceptions(env, GETPC());
return RET128(ret);
}
/* convert 32-bit float to 64-bit float */
uint64_t HELPER(ldeb)(CPUS390XState *env, uint64_t f2)
{
float64 ret = float32_to_float64(f2, &env->fpu_status);
handle_exceptions(env, GETPC());
return float64_maybe_silence_nan(ret);
}
/* convert 128-bit float to 64-bit float */
uint64_t HELPER(ldxb)(CPUS390XState *env, uint64_t ah, uint64_t al)
{
float64 ret = float128_to_float64(make_float128(ah, al), &env->fpu_status);
handle_exceptions(env, GETPC());
return float64_maybe_silence_nan(ret);
}
/* convert 64-bit float to 128-bit float */
uint64_t HELPER(lxdb)(CPUS390XState *env, uint64_t f2)
{
float128 ret = float64_to_float128(f2, &env->fpu_status);
handle_exceptions(env, GETPC());
return RET128(float128_maybe_silence_nan(ret));
}
/* convert 32-bit float to 128-bit float */
uint64_t HELPER(lxeb)(CPUS390XState *env, uint64_t f2)
{
float128 ret = float32_to_float128(f2, &env->fpu_status);
handle_exceptions(env, GETPC());
return RET128(float128_maybe_silence_nan(ret));
}
/* convert 64-bit float to 32-bit float */
uint64_t HELPER(ledb)(CPUS390XState *env, uint64_t f2)
{
float32 ret = float64_to_float32(f2, &env->fpu_status);
handle_exceptions(env, GETPC());
return float32_maybe_silence_nan(ret);
}
/* convert 128-bit float to 32-bit float */
uint64_t HELPER(lexb)(CPUS390XState *env, uint64_t ah, uint64_t al)
{
float32 ret = float128_to_float32(make_float128(ah, al), &env->fpu_status);
handle_exceptions(env, GETPC());
return float32_maybe_silence_nan(ret);
}
/* 32-bit FP compare */
uint32_t HELPER(ceb)(CPUS390XState *env, uint64_t f1, uint64_t f2)
{
int cmp = float32_compare_quiet(f1, f2, &env->fpu_status);
handle_exceptions(env, GETPC());
return float_comp_to_cc(env, cmp);
}
/* 64-bit FP compare */
uint32_t HELPER(cdb)(CPUS390XState *env, uint64_t f1, uint64_t f2)
{
int cmp = float64_compare_quiet(f1, f2, &env->fpu_status);
handle_exceptions(env, GETPC());
return float_comp_to_cc(env, cmp);
}
/* 128-bit FP compare */
uint32_t HELPER(cxb)(CPUS390XState *env, uint64_t ah, uint64_t al,
uint64_t bh, uint64_t bl)
{
int cmp = float128_compare_quiet(make_float128(ah, al),
make_float128(bh, bl),
&env->fpu_status);
handle_exceptions(env, GETPC());
return float_comp_to_cc(env, cmp);
}
static int swap_round_mode(CPUS390XState *env, int m3)
{
int ret = env->fpu_status.float_rounding_mode;
switch (m3) {
case 0:
/* current mode */
break;
case 1:
/* biased round no nearest */
case 4:
/* round to nearest */
set_float_rounding_mode(float_round_nearest_even, &env->fpu_status);
break;
case 5:
/* round to zero */
set_float_rounding_mode(float_round_to_zero, &env->fpu_status);
break;
case 6:
/* round to +inf */
set_float_rounding_mode(float_round_up, &env->fpu_status);
break;
case 7:
/* round to -inf */
set_float_rounding_mode(float_round_down, &env->fpu_status);
break;
}
return ret;
}
/* convert 64-bit int to 32-bit float */
uint64_t HELPER(cegb)(CPUS390XState *env, int64_t v2, uint32_t m3)
{
int hold = swap_round_mode(env, m3);
float32 ret = int64_to_float32(v2, &env->fpu_status);
set_float_rounding_mode(hold, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* convert 64-bit int to 64-bit float */
uint64_t HELPER(cdgb)(CPUS390XState *env, int64_t v2, uint32_t m3)
{
int hold = swap_round_mode(env, m3);
float64 ret = int64_to_float64(v2, &env->fpu_status);
set_float_rounding_mode(hold, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* convert 64-bit int to 128-bit float */
uint64_t HELPER(cxgb)(CPUS390XState *env, int64_t v2, uint32_t m3)
{
int hold = swap_round_mode(env, m3);
float128 ret = int64_to_float128(v2, &env->fpu_status);
set_float_rounding_mode(hold, &env->fpu_status);
handle_exceptions(env, GETPC());
return RET128(ret);
}
/* convert 64-bit uint to 32-bit float */
uint64_t HELPER(celgb)(CPUS390XState *env, uint64_t v2, uint32_t m3)
{
int hold = swap_round_mode(env, m3);
float32 ret = uint64_to_float32(v2, &env->fpu_status);
set_float_rounding_mode(hold, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* convert 64-bit uint to 64-bit float */
uint64_t HELPER(cdlgb)(CPUS390XState *env, uint64_t v2, uint32_t m3)
{
int hold = swap_round_mode(env, m3);
float64 ret = uint64_to_float64(v2, &env->fpu_status);
set_float_rounding_mode(hold, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* convert 64-bit uint to 128-bit float */
uint64_t HELPER(cxlgb)(CPUS390XState *env, uint64_t v2, uint32_t m3)
{
int hold = swap_round_mode(env, m3);
float128 ret = uint64_to_float128(v2, &env->fpu_status);
set_float_rounding_mode(hold, &env->fpu_status);
handle_exceptions(env, GETPC());
return RET128(ret);
}
/* convert 32-bit float to 64-bit int */
uint64_t HELPER(cgeb)(CPUS390XState *env, uint64_t v2, uint32_t m3)
{
int hold = swap_round_mode(env, m3);
int64_t ret = float32_to_int64(v2, &env->fpu_status);
set_float_rounding_mode(hold, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* convert 64-bit float to 64-bit int */
uint64_t HELPER(cgdb)(CPUS390XState *env, uint64_t v2, uint32_t m3)
{
int hold = swap_round_mode(env, m3);
int64_t ret = float64_to_int64(v2, &env->fpu_status);
set_float_rounding_mode(hold, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* convert 128-bit float to 64-bit int */
uint64_t HELPER(cgxb)(CPUS390XState *env, uint64_t h, uint64_t l, uint32_t m3)
{
int hold = swap_round_mode(env, m3);
float128 v2 = make_float128(h, l);
int64_t ret = float128_to_int64(v2, &env->fpu_status);
set_float_rounding_mode(hold, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* convert 32-bit float to 32-bit int */
uint64_t HELPER(cfeb)(CPUS390XState *env, uint64_t v2, uint32_t m3)
{
int hold = swap_round_mode(env, m3);
int32_t ret = float32_to_int32(v2, &env->fpu_status);
set_float_rounding_mode(hold, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* convert 64-bit float to 32-bit int */
uint64_t HELPER(cfdb)(CPUS390XState *env, uint64_t v2, uint32_t m3)
{
int hold = swap_round_mode(env, m3);
int32_t ret = float64_to_int32(v2, &env->fpu_status);
set_float_rounding_mode(hold, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* convert 128-bit float to 32-bit int */
uint64_t HELPER(cfxb)(CPUS390XState *env, uint64_t h, uint64_t l, uint32_t m3)
{
int hold = swap_round_mode(env, m3);
float128 v2 = make_float128(h, l);
int32_t ret = float128_to_int32(v2, &env->fpu_status);
set_float_rounding_mode(hold, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* convert 32-bit float to 64-bit uint */
uint64_t HELPER(clgeb)(CPUS390XState *env, uint64_t v2, uint32_t m3)
{
int hold = swap_round_mode(env, m3);
uint64_t ret;
v2 = float32_to_float64(v2, &env->fpu_status);
ret = float64_to_uint64(v2, &env->fpu_status);
set_float_rounding_mode(hold, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* convert 64-bit float to 64-bit uint */
uint64_t HELPER(clgdb)(CPUS390XState *env, uint64_t v2, uint32_t m3)
{
int hold = swap_round_mode(env, m3);
uint64_t ret = float64_to_uint64(v2, &env->fpu_status);
set_float_rounding_mode(hold, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* convert 128-bit float to 64-bit uint */
uint64_t HELPER(clgxb)(CPUS390XState *env, uint64_t h, uint64_t l, uint32_t m3)
{
int hold = swap_round_mode(env, m3);
float128 v2 = make_float128(h, l);
/* ??? Not 100% correct. */
uint64_t ret = float128_to_int64(v2, &env->fpu_status);
set_float_rounding_mode(hold, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* convert 32-bit float to 32-bit uint */
uint64_t HELPER(clfeb)(CPUS390XState *env, uint64_t v2, uint32_t m3)
{
int hold = swap_round_mode(env, m3);
uint32_t ret = float32_to_uint32(v2, &env->fpu_status);
set_float_rounding_mode(hold, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* convert 64-bit float to 32-bit uint */
uint64_t HELPER(clfdb)(CPUS390XState *env, uint64_t v2, uint32_t m3)
{
int hold = swap_round_mode(env, m3);
uint32_t ret = float64_to_uint32(v2, &env->fpu_status);
set_float_rounding_mode(hold, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* convert 128-bit float to 32-bit uint */
uint64_t HELPER(clfxb)(CPUS390XState *env, uint64_t h, uint64_t l, uint32_t m3)
{
int hold = swap_round_mode(env, m3);
float128 v2 = make_float128(h, l);
/* Not 100% correct. */
uint32_t ret = float128_to_int64(v2, &env->fpu_status);
set_float_rounding_mode(hold, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* round to integer 32-bit */
uint64_t HELPER(fieb)(CPUS390XState *env, uint64_t f2, uint32_t m3)
{
int hold = swap_round_mode(env, m3);
float32 ret = float32_round_to_int(f2, &env->fpu_status);
set_float_rounding_mode(hold, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* round to integer 64-bit */
uint64_t HELPER(fidb)(CPUS390XState *env, uint64_t f2, uint32_t m3)
{
int hold = swap_round_mode(env, m3);
float64 ret = float64_round_to_int(f2, &env->fpu_status);
set_float_rounding_mode(hold, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* round to integer 128-bit */
uint64_t HELPER(fixb)(CPUS390XState *env, uint64_t ah, uint64_t al, uint32_t m3)
{
int hold = swap_round_mode(env, m3);
float128 ret = float128_round_to_int(make_float128(ah, al),
&env->fpu_status);
set_float_rounding_mode(hold, &env->fpu_status);
handle_exceptions(env, GETPC());
return RET128(ret);
}
/* 32-bit FP multiply and add */
uint64_t HELPER(maeb)(CPUS390XState *env, uint64_t f1,
uint64_t f2, uint64_t f3)
{
float32 ret = float32_muladd(f2, f3, f1, 0, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* 64-bit FP multiply and add */
uint64_t HELPER(madb)(CPUS390XState *env, uint64_t f1,
uint64_t f2, uint64_t f3)
{
float64 ret = float64_muladd(f2, f3, f1, 0, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* 32-bit FP multiply and subtract */
uint64_t HELPER(mseb)(CPUS390XState *env, uint64_t f1,
uint64_t f2, uint64_t f3)
{
float32 ret = float32_muladd(f2, f3, f1, float_muladd_negate_c,
&env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* 64-bit FP multiply and subtract */
uint64_t HELPER(msdb)(CPUS390XState *env, uint64_t f1,
uint64_t f2, uint64_t f3)
{
float64 ret = float64_muladd(f2, f3, f1, float_muladd_negate_c,
&env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* test data class 32-bit */
uint32_t HELPER(tceb)(uint64_t f1, uint64_t m2)
{
float32 v1 = f1;
int neg = float32_is_neg(v1);
uint32_t cc = 0;
if ((float32_is_zero(v1) && (m2 & (1 << (11-neg)))) ||
(float32_is_infinity(v1) && (m2 & (1 << (5-neg)))) ||
(float32_is_any_nan(v1) && (m2 & (1 << (3-neg)))) ||
(float32_is_signaling_nan(v1) && (m2 & (1 << (1-neg))))) {
cc = 1;
} else if (m2 & (1 << (9-neg))) {
/* assume normalized number */
cc = 1;
}
/* FIXME: denormalized? */
return cc;
}
/* test data class 64-bit */
uint32_t HELPER(tcdb)(uint64_t v1, uint64_t m2)
{
int neg = float64_is_neg(v1);
uint32_t cc = 0;
if ((float64_is_zero(v1) && (m2 & (1 << (11-neg)))) ||
(float64_is_infinity(v1) && (m2 & (1 << (5-neg)))) ||
(float64_is_any_nan(v1) && (m2 & (1 << (3-neg)))) ||
(float64_is_signaling_nan(v1) && (m2 & (1 << (1-neg))))) {
cc = 1;
} else if (m2 & (1 << (9-neg))) {
/* assume normalized number */
cc = 1;
}
/* FIXME: denormalized? */
return cc;
}
/* test data class 128-bit */
uint32_t HELPER(tcxb)(uint64_t ah, uint64_t al, uint64_t m2)
{
float128 v1 = make_float128(ah, al);
int neg = float128_is_neg(v1);
uint32_t cc = 0;
if ((float128_is_zero(v1) && (m2 & (1 << (11-neg)))) ||
(float128_is_infinity(v1) && (m2 & (1 << (5-neg)))) ||
(float128_is_any_nan(v1) && (m2 & (1 << (3-neg)))) ||
(float128_is_signaling_nan(v1) && (m2 & (1 << (1-neg))))) {
cc = 1;
} else if (m2 & (1 << (9-neg))) {
/* assume normalized number */
cc = 1;
}
/* FIXME: denormalized? */
return cc;
}
/* square root 32-bit */
uint64_t HELPER(sqeb)(CPUS390XState *env, uint64_t f2)
{
float32 ret = float32_sqrt(f2, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* square root 64-bit */
uint64_t HELPER(sqdb)(CPUS390XState *env, uint64_t f2)
{
float64 ret = float64_sqrt(f2, &env->fpu_status);
handle_exceptions(env, GETPC());
return ret;
}
/* square root 128-bit */
uint64_t HELPER(sqxb)(CPUS390XState *env, uint64_t ah, uint64_t al)
{
float128 ret = float128_sqrt(make_float128(ah, al), &env->fpu_status);
handle_exceptions(env, GETPC());
return RET128(ret);
}
static const int fpc_to_rnd[4] = {
float_round_nearest_even,
float_round_to_zero,
float_round_up,
float_round_down
};
/* set fpc */
void HELPER(sfpc)(CPUS390XState *env, uint64_t fpc)
{
/* Install everything in the main FPC. */
env->fpc = fpc;
/* Install the rounding mode in the shadow fpu_status. */
set_float_rounding_mode(fpc_to_rnd[fpc & 3], &env->fpu_status);
}
/* set fpc and signal */
void HELPER(sfas)(CPUS390XState *env, uint64_t val)
{
uint32_t signalling = env->fpc;
uint32_t source = val;
uint32_t s390_exc;
/* The contents of the source operand are placed in the FPC register;
then the flags in the FPC register are set to the logical OR of the
signalling flags and the source flags. */
env->fpc = source | (signalling & 0x00ff0000);
set_float_rounding_mode(fpc_to_rnd[source & 3], &env->fpu_status);
/* If any signalling flag is 1 and the corresponding source mask
is also 1, a simulated-iee-exception trap occurs. */
s390_exc = (signalling >> 16) & (source >> 24);
if (s390_exc) {
ieee_exception(env, s390_exc | 3, GETPC());
}
}