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/*
* PowerPC Decimal Floating Point (DPF) emulation helpers for QEMU.
*
* Copyright (c) 2014 IBM Corporation.
*
* 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/helper-proto.h"
#define DECNUMDIGITS 34
#include "libdecnumber/decContext.h"
#include "libdecnumber/decNumber.h"
#include "libdecnumber/dpd/decimal32.h"
#include "libdecnumber/dpd/decimal64.h"
#include "libdecnumber/dpd/decimal128.h"
#if defined(HOST_WORDS_BIGENDIAN)
#define HI_IDX 0
#define LO_IDX 1
#else
#define HI_IDX 1
#define LO_IDX 0
#endif
struct PPC_DFP {
CPUPPCState *env;
uint64_t t64[2], a64[2], b64[2];
decNumber t, a, b;
decContext context;
uint8_t crbf;
};
static void dfp_prepare_rounding_mode(decContext *context, uint64_t fpscr)
{
enum rounding rnd;
switch ((fpscr >> 32) & 0x7) {
case 0:
rnd = DEC_ROUND_HALF_EVEN;
break;
case 1:
rnd = DEC_ROUND_DOWN;
break;
case 2:
rnd = DEC_ROUND_CEILING;
break;
case 3:
rnd = DEC_ROUND_FLOOR;
break;
case 4:
rnd = DEC_ROUND_HALF_UP;
break;
case 5:
rnd = DEC_ROUND_HALF_DOWN;
break;
case 6:
rnd = DEC_ROUND_UP;
break;
case 7:
rnd = DEC_ROUND_05UP;
break;
default:
g_assert_not_reached();
}
decContextSetRounding(context, rnd);
}
static void dfp_prepare_decimal64(struct PPC_DFP *dfp, uint64_t *a,
uint64_t *b, CPUPPCState *env)
{
decContextDefault(&dfp->context, DEC_INIT_DECIMAL64);
dfp_prepare_rounding_mode(&dfp->context, env->fpscr);
dfp->env = env;
if (a) {
dfp->a64[0] = *a;
decimal64ToNumber((decimal64 *)dfp->a64, &dfp->a);
} else {
dfp->a64[0] = 0;
decNumberZero(&dfp->a);
}
if (b) {
dfp->b64[0] = *b;
decimal64ToNumber((decimal64 *)dfp->b64, &dfp->b);
} else {
dfp->b64[0] = 0;
decNumberZero(&dfp->b);
}
}
static void dfp_prepare_decimal128(struct PPC_DFP *dfp, uint64_t *a,
uint64_t *b, CPUPPCState *env)
{
decContextDefault(&dfp->context, DEC_INIT_DECIMAL128);
dfp_prepare_rounding_mode(&dfp->context, env->fpscr);
dfp->env = env;
if (a) {
dfp->a64[0] = a[HI_IDX];
dfp->a64[1] = a[LO_IDX];
decimal128ToNumber((decimal128 *)dfp->a64, &dfp->a);
} else {
dfp->a64[0] = dfp->a64[1] = 0;
decNumberZero(&dfp->a);
}
if (b) {
dfp->b64[0] = b[HI_IDX];
dfp->b64[1] = b[LO_IDX];
decimal128ToNumber((decimal128 *)dfp->b64, &dfp->b);
} else {
dfp->b64[0] = dfp->b64[1] = 0;
decNumberZero(&dfp->b);
}
}
#define FP_FX (1ull << FPSCR_FX)
#define FP_FEX (1ull << FPSCR_FEX)
#define FP_OX (1ull << FPSCR_OX)
#define FP_OE (1ull << FPSCR_OE)
#define FP_UX (1ull << FPSCR_UX)
#define FP_UE (1ull << FPSCR_UE)
#define FP_XX (1ull << FPSCR_XX)
#define FP_XE (1ull << FPSCR_XE)
#define FP_ZX (1ull << FPSCR_ZX)
#define FP_ZE (1ull << FPSCR_ZE)
#define FP_VX (1ull << FPSCR_VX)
#define FP_VXSNAN (1ull << FPSCR_VXSNAN)
#define FP_VXISI (1ull << FPSCR_VXISI)
#define FP_VXIMZ (1ull << FPSCR_VXIMZ)
#define FP_VXZDZ (1ull << FPSCR_VXZDZ)
#define FP_VXIDI (1ull << FPSCR_VXIDI)
#define FP_VXVC (1ull << FPSCR_VXVC)
#define FP_VXCVI (1ull << FPSCR_VXCVI)
#define FP_VE (1ull << FPSCR_VE)
#define FP_FI (1ull << FPSCR_FI)
static void dfp_set_FPSCR_flag(struct PPC_DFP *dfp, uint64_t flag,
uint64_t enabled)
{
dfp->env->fpscr |= (flag | FP_FX);
if (dfp->env->fpscr & enabled) {
dfp->env->fpscr |= FP_FEX;
}
}
static void dfp_set_FPRF_from_FRT_with_context(struct PPC_DFP *dfp,
decContext *context)
{
uint64_t fprf = 0;
/* construct FPRF */
switch (decNumberClass(&dfp->t, context)) {
case DEC_CLASS_SNAN:
fprf = 0x01;
break;
case DEC_CLASS_QNAN:
fprf = 0x11;
break;
case DEC_CLASS_NEG_INF:
fprf = 0x09;
break;
case DEC_CLASS_NEG_NORMAL:
fprf = 0x08;
break;
case DEC_CLASS_NEG_SUBNORMAL:
fprf = 0x18;
break;
case DEC_CLASS_NEG_ZERO:
fprf = 0x12;
break;
case DEC_CLASS_POS_ZERO:
fprf = 0x02;
break;
case DEC_CLASS_POS_SUBNORMAL:
fprf = 0x14;
break;
case DEC_CLASS_POS_NORMAL:
fprf = 0x04;
break;
case DEC_CLASS_POS_INF:
fprf = 0x05;
break;
default:
assert(0); /* should never get here */
}
dfp->env->fpscr &= ~(0x1F << 12);
dfp->env->fpscr |= (fprf << 12);
}
static void dfp_set_FPRF_from_FRT(struct PPC_DFP *dfp)
{
dfp_set_FPRF_from_FRT_with_context(dfp, &dfp->context);
}
static void dfp_check_for_OX(struct PPC_DFP *dfp)
{
if (dfp->context.status & DEC_Overflow) {
dfp_set_FPSCR_flag(dfp, FP_OX, FP_OE);
}
}
static void dfp_check_for_UX(struct PPC_DFP *dfp)
{
if (dfp->context.status & DEC_Underflow) {
dfp_set_FPSCR_flag(dfp, FP_UX, FP_UE);
}
}
static void dfp_check_for_XX(struct PPC_DFP *dfp)
{
if (dfp->context.status & DEC_Inexact) {
dfp_set_FPSCR_flag(dfp, FP_XX | FP_FI, FP_XE);
}
}
static void dfp_check_for_VXSNAN(struct PPC_DFP *dfp)
{
if (dfp->context.status & DEC_Invalid_operation) {
if (decNumberIsSNaN(&dfp->a) || decNumberIsSNaN(&dfp->b)) {
dfp_set_FPSCR_flag(dfp, FP_VX | FP_VXSNAN, FP_VE);
}
}
}
static void dfp_check_for_VXISI(struct PPC_DFP *dfp, int testForSameSign)
{
if (dfp->context.status & DEC_Invalid_operation) {
if (decNumberIsInfinite(&dfp->a) && decNumberIsInfinite(&dfp->b)) {
int same = decNumberClass(&dfp->a, &dfp->context) ==
decNumberClass(&dfp->b, &dfp->context);
if ((same && testForSameSign) || (!same && !testForSameSign)) {
dfp_set_FPSCR_flag(dfp, FP_VX | FP_VXISI, FP_VE);
}
}
}
}
static void dfp_check_for_VXISI_add(struct PPC_DFP *dfp)
{
dfp_check_for_VXISI(dfp, 0);
}
static void dfp_check_for_VXISI_subtract(struct PPC_DFP *dfp)
{
dfp_check_for_VXISI(dfp, 1);
}
#define DFP_HELPER_TAB(op, dnop, postprocs, size) \
void helper_##op(CPUPPCState *env, uint64_t *t, uint64_t *a, uint64_t *b) \
{ \
struct PPC_DFP dfp; \
dfp_prepare_decimal##size(&dfp, a, b, env); \
dnop(&dfp.t, &dfp.a, &dfp.b, &dfp.context); \
decimal##size##FromNumber((decimal##size *)dfp.t64, &dfp.t, &dfp.context); \
postprocs(&dfp); \
if (size == 64) { \
t[0] = dfp.t64[0]; \
} else if (size == 128) { \
t[0] = dfp.t64[HI_IDX]; \
t[1] = dfp.t64[LO_IDX]; \
} \
}
static void ADD_PPs(struct PPC_DFP *dfp)
{
dfp_set_FPRF_from_FRT(dfp);
dfp_check_for_OX(dfp);
dfp_check_for_UX(dfp);
dfp_check_for_XX(dfp);
dfp_check_for_VXSNAN(dfp);
dfp_check_for_VXISI_add(dfp);
}
DFP_HELPER_TAB(dadd, decNumberAdd, ADD_PPs, 64)
DFP_HELPER_TAB(daddq, decNumberAdd, ADD_PPs, 128)
static void SUB_PPs(struct PPC_DFP *dfp)
{
dfp_set_FPRF_from_FRT(dfp);
dfp_check_for_OX(dfp);
dfp_check_for_UX(dfp);
dfp_check_for_XX(dfp);
dfp_check_for_VXSNAN(dfp);
dfp_check_for_VXISI_subtract(dfp);
}
DFP_HELPER_TAB(dsub, decNumberSubtract, SUB_PPs, 64)
DFP_HELPER_TAB(dsubq, decNumberSubtract, SUB_PPs, 128)
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