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qemu-patch-raspberry4/target-s390x/cc_helper.c
Torbjorn Granlund 9ef1473693 target-s390x: fix and optimize slb* and slbg* computation of carry/borrow flag 
This patch fixes the bug with borrow_in being set incorrectly, but it
also simplifies the logic to be much more plain, improving speed.  It
fixes both the 32-bit SLB* and 64-bit SLBG*.

The SLBG* change has been well-tested.  I haven't tested the SLB* change
explicitly, but the code was copy-pasted from the tested code.

The error of these functions' current implementations would not likely
be triggered by compiler-generated code, since the only error was in the
state of the carry/borrow flag.  Compilers rarely generate an
instruction sequence such as carry-set -> carry-set-and-use ->
carry-use.

(With Paolo's fix and mine, there are still a couple of failures from
GMP's testsuite, but they are almost surely due to incorrect code
generation from gcc 4.9.  But since this gcc is running under qemu, it
might be qemu bugs.  I intend to investigate this.)

Signed-off-by: Torbjorn Granlund <torbjorng@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2015-02-03 12:27:05 -08:00

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/*
* S/390 condition code 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/helper-proto.h"
#include "qemu/host-utils.h"
/* #define DEBUG_HELPER */
#ifdef DEBUG_HELPER
#define HELPER_LOG(x...) qemu_log(x)
#else
#define HELPER_LOG(x...)
#endif
static uint32_t cc_calc_ltgt_32(int32_t src, int32_t dst)
{
if (src == dst) {
return 0;
} else if (src < dst) {
return 1;
} else {
return 2;
}
}
static uint32_t cc_calc_ltgt0_32(int32_t dst)
{
return cc_calc_ltgt_32(dst, 0);
}
static uint32_t cc_calc_ltgt_64(int64_t src, int64_t dst)
{
if (src == dst) {
return 0;
} else if (src < dst) {
return 1;
} else {
return 2;
}
}
static uint32_t cc_calc_ltgt0_64(int64_t dst)
{
return cc_calc_ltgt_64(dst, 0);
}
static uint32_t cc_calc_ltugtu_32(uint32_t src, uint32_t dst)
{
if (src == dst) {
return 0;
} else if (src < dst) {
return 1;
} else {
return 2;
}
}
static uint32_t cc_calc_ltugtu_64(uint64_t src, uint64_t dst)
{
if (src == dst) {
return 0;
} else if (src < dst) {
return 1;
} else {
return 2;
}
}
static uint32_t cc_calc_tm_32(uint32_t val, uint32_t mask)
{
uint32_t r = val & mask;
if (r == 0) {
return 0;
} else if (r == mask) {
return 3;
} else {
return 1;
}
}
static uint32_t cc_calc_tm_64(uint64_t val, uint64_t mask)
{
uint64_t r = val & mask;
if (r == 0) {
return 0;
} else if (r == mask) {
return 3;
} else {
int top = clz64(mask);
if ((int64_t)(val << top) < 0) {
return 2;
} else {
return 1;
}
}
}
static uint32_t cc_calc_nz(uint64_t dst)
{
return !!dst;
}
static uint32_t cc_calc_add_64(int64_t a1, int64_t a2, int64_t ar)
{
if ((a1 > 0 && a2 > 0 && ar < 0) || (a1 < 0 && a2 < 0 && ar > 0)) {
return 3; /* overflow */
} else {
if (ar < 0) {
return 1;
} else if (ar > 0) {
return 2;
} else {
return 0;
}
}
}
static uint32_t cc_calc_addu_64(uint64_t a1, uint64_t a2, uint64_t ar)
{
return (ar != 0) + 2 * (ar < a1);
}
static uint32_t cc_calc_addc_64(uint64_t a1, uint64_t a2, uint64_t ar)
{
/* Recover a2 + carry_in. */
uint64_t a2c = ar - a1;
/* Check for a2+carry_in overflow, then a1+a2c overflow. */
int carry_out = (a2c < a2) || (ar < a1);
return (ar != 0) + 2 * carry_out;
}
static uint32_t cc_calc_sub_64(int64_t a1, int64_t a2, int64_t ar)
{
if ((a1 > 0 && a2 < 0 && ar < 0) || (a1 < 0 && a2 > 0 && ar > 0)) {
return 3; /* overflow */
} else {
if (ar < 0) {
return 1;
} else if (ar > 0) {
return 2;
} else {
return 0;
}
}
}
static uint32_t cc_calc_subu_64(uint64_t a1, uint64_t a2, uint64_t ar)
{
if (ar == 0) {
return 2;
} else {
if (a2 > a1) {
return 1;
} else {
return 3;
}
}
}
static uint32_t cc_calc_subb_64(uint64_t a1, uint64_t a2, uint64_t ar)
{
int borrow_out;
if (ar != a1 - a2) { /* difference means borrow-in */
borrow_out = (a2 >= a1);
} else {
borrow_out = (a2 > a1);
}
return (ar != 0) + 2 * !borrow_out;
}
static uint32_t cc_calc_abs_64(int64_t dst)
{
if ((uint64_t)dst == 0x8000000000000000ULL) {
return 3;
} else if (dst) {
return 1;
} else {
return 0;
}
}
static uint32_t cc_calc_nabs_64(int64_t dst)
{
return !!dst;
}
static uint32_t cc_calc_comp_64(int64_t dst)
{
if ((uint64_t)dst == 0x8000000000000000ULL) {
return 3;
} else if (dst < 0) {
return 1;
} else if (dst > 0) {
return 2;
} else {
return 0;
}
}
static uint32_t cc_calc_add_32(int32_t a1, int32_t a2, int32_t ar)
{
if ((a1 > 0 && a2 > 0 && ar < 0) || (a1 < 0 && a2 < 0 && ar > 0)) {
return 3; /* overflow */
} else {
if (ar < 0) {
return 1;
} else if (ar > 0) {
return 2;
} else {
return 0;
}
}
}
static uint32_t cc_calc_addu_32(uint32_t a1, uint32_t a2, uint32_t ar)
{
return (ar != 0) + 2 * (ar < a1);
}
static uint32_t cc_calc_addc_32(uint32_t a1, uint32_t a2, uint32_t ar)
{
/* Recover a2 + carry_in. */
uint32_t a2c = ar - a1;
/* Check for a2+carry_in overflow, then a1+a2c overflow. */
int carry_out = (a2c < a2) || (ar < a1);
return (ar != 0) + 2 * carry_out;
}
static uint32_t cc_calc_sub_32(int32_t a1, int32_t a2, int32_t ar)
{
if ((a1 > 0 && a2 < 0 && ar < 0) || (a1 < 0 && a2 > 0 && ar > 0)) {
return 3; /* overflow */
} else {
if (ar < 0) {
return 1;
} else if (ar > 0) {
return 2;
} else {
return 0;
}
}
}
static uint32_t cc_calc_subu_32(uint32_t a1, uint32_t a2, uint32_t ar)
{
if (ar == 0) {
return 2;
} else {
if (a2 > a1) {
return 1;
} else {
return 3;
}
}
}
static uint32_t cc_calc_subb_32(uint32_t a1, uint32_t a2, uint32_t ar)
{
int borrow_out;
if (ar != a1 - a2) { /* difference means borrow-in */
borrow_out = (a2 >= a1);
} else {
borrow_out = (a2 > a1);
}
return (ar != 0) + 2 * !borrow_out;
}
static uint32_t cc_calc_abs_32(int32_t dst)
{
if ((uint32_t)dst == 0x80000000UL) {
return 3;
} else if (dst) {
return 1;
} else {
return 0;
}
}
static uint32_t cc_calc_nabs_32(int32_t dst)
{
return !!dst;
}
static uint32_t cc_calc_comp_32(int32_t dst)
{
if ((uint32_t)dst == 0x80000000UL) {
return 3;
} else if (dst < 0) {
return 1;
} else if (dst > 0) {
return 2;
} else {
return 0;
}
}
/* calculate condition code for insert character under mask insn */
static uint32_t cc_calc_icm(uint64_t mask, uint64_t val)
{
if ((val & mask) == 0) {
return 0;
} else {
int top = clz64(mask);
if ((int64_t)(val << top) < 0) {
return 1;
} else {
return 2;
}
}
}
static uint32_t cc_calc_sla_32(uint32_t src, int shift)
{
uint32_t mask = ((1U << shift) - 1U) << (32 - shift);
uint32_t sign = 1U << 31;
uint32_t match;
int32_t r;
/* Check if the sign bit stays the same. */
if (src & sign) {
match = mask;
} else {
match = 0;
}
if ((src & mask) != match) {
/* Overflow. */
return 3;
}
r = ((src << shift) & ~sign) | (src & sign);
if (r == 0) {
return 0;
} else if (r < 0) {
return 1;
}
return 2;
}
static uint32_t cc_calc_sla_64(uint64_t src, int shift)
{
uint64_t mask = ((1ULL << shift) - 1ULL) << (64 - shift);
uint64_t sign = 1ULL << 63;
uint64_t match;
int64_t r;
/* Check if the sign bit stays the same. */
if (src & sign) {
match = mask;
} else {
match = 0;
}
if ((src & mask) != match) {
/* Overflow. */
return 3;
}
r = ((src << shift) & ~sign) | (src & sign);
if (r == 0) {
return 0;
} else if (r < 0) {
return 1;
}
return 2;
}
static uint32_t cc_calc_flogr(uint64_t dst)
{
return dst ? 2 : 0;
}
static uint32_t do_calc_cc(CPUS390XState *env, uint32_t cc_op,
uint64_t src, uint64_t dst, uint64_t vr)
{
S390CPU *cpu = s390_env_get_cpu(env);
uint32_t r = 0;
switch (cc_op) {
case CC_OP_CONST0:
case CC_OP_CONST1:
case CC_OP_CONST2:
case CC_OP_CONST3:
/* cc_op value _is_ cc */
r = cc_op;
break;
case CC_OP_LTGT0_32:
r = cc_calc_ltgt0_32(dst);
break;
case CC_OP_LTGT0_64:
r = cc_calc_ltgt0_64(dst);
break;
case CC_OP_LTGT_32:
r = cc_calc_ltgt_32(src, dst);
break;
case CC_OP_LTGT_64:
r = cc_calc_ltgt_64(src, dst);
break;
case CC_OP_LTUGTU_32:
r = cc_calc_ltugtu_32(src, dst);
break;
case CC_OP_LTUGTU_64:
r = cc_calc_ltugtu_64(src, dst);
break;
case CC_OP_TM_32:
r = cc_calc_tm_32(src, dst);
break;
case CC_OP_TM_64:
r = cc_calc_tm_64(src, dst);
break;
case CC_OP_NZ:
r = cc_calc_nz(dst);
break;
case CC_OP_ADD_64:
r = cc_calc_add_64(src, dst, vr);
break;
case CC_OP_ADDU_64:
r = cc_calc_addu_64(src, dst, vr);
break;
case CC_OP_ADDC_64:
r = cc_calc_addc_64(src, dst, vr);
break;
case CC_OP_SUB_64:
r = cc_calc_sub_64(src, dst, vr);
break;
case CC_OP_SUBU_64:
r = cc_calc_subu_64(src, dst, vr);
break;
case CC_OP_SUBB_64:
r = cc_calc_subb_64(src, dst, vr);
break;
case CC_OP_ABS_64:
r = cc_calc_abs_64(dst);
break;
case CC_OP_NABS_64:
r = cc_calc_nabs_64(dst);
break;
case CC_OP_COMP_64:
r = cc_calc_comp_64(dst);
break;
case CC_OP_ADD_32:
r = cc_calc_add_32(src, dst, vr);
break;
case CC_OP_ADDU_32:
r = cc_calc_addu_32(src, dst, vr);
break;
case CC_OP_ADDC_32:
r = cc_calc_addc_32(src, dst, vr);
break;
case CC_OP_SUB_32:
r = cc_calc_sub_32(src, dst, vr);
break;
case CC_OP_SUBU_32:
r = cc_calc_subu_32(src, dst, vr);
break;
case CC_OP_SUBB_32:
r = cc_calc_subb_32(src, dst, vr);
break;
case CC_OP_ABS_32:
r = cc_calc_abs_32(dst);
break;
case CC_OP_NABS_32:
r = cc_calc_nabs_32(dst);
break;
case CC_OP_COMP_32:
r = cc_calc_comp_32(dst);
break;
case CC_OP_ICM:
r = cc_calc_icm(src, dst);
break;
case CC_OP_SLA_32:
r = cc_calc_sla_32(src, dst);
break;
case CC_OP_SLA_64:
r = cc_calc_sla_64(src, dst);
break;
case CC_OP_FLOGR:
r = cc_calc_flogr(dst);
break;
case CC_OP_NZ_F32:
r = set_cc_nz_f32(dst);
break;
case CC_OP_NZ_F64:
r = set_cc_nz_f64(dst);
break;
case CC_OP_NZ_F128:
r = set_cc_nz_f128(make_float128(src, dst));
break;
default:
cpu_abort(CPU(cpu), "Unknown CC operation: %s\n", cc_name(cc_op));
}
HELPER_LOG("%s: %15s 0x%016lx 0x%016lx 0x%016lx = %d\n", __func__,
cc_name(cc_op), src, dst, vr, r);
return r;
}
uint32_t calc_cc(CPUS390XState *env, uint32_t cc_op, uint64_t src, uint64_t dst,
uint64_t vr)
{
return do_calc_cc(env, cc_op, src, dst, vr);
}
uint32_t HELPER(calc_cc)(CPUS390XState *env, uint32_t cc_op, uint64_t src,
uint64_t dst, uint64_t vr)
{
return do_calc_cc(env, cc_op, src, dst, vr);
}
#ifndef CONFIG_USER_ONLY
void HELPER(load_psw)(CPUS390XState *env, uint64_t mask, uint64_t addr)
{
load_psw(env, mask, addr);
cpu_loop_exit(CPU(s390_env_get_cpu(env)));
}
void HELPER(sacf)(CPUS390XState *env, uint64_t a1)
{
HELPER_LOG("%s: %16" PRIx64 "\n", __func__, a1);
switch (a1 & 0xf00) {
case 0x000:
env->psw.mask &= ~PSW_MASK_ASC;
env->psw.mask |= PSW_ASC_PRIMARY;
break;
case 0x100:
env->psw.mask &= ~PSW_MASK_ASC;
env->psw.mask |= PSW_ASC_SECONDARY;
break;
case 0x300:
env->psw.mask &= ~PSW_MASK_ASC;
env->psw.mask |= PSW_ASC_HOME;
break;
default:
qemu_log("unknown sacf mode: %" PRIx64 "\n", a1);
program_interrupt(env, PGM_SPECIFICATION, 2);
break;
}
}
#endif
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