qemu-e2k/target/openrisc/exception_helper.c
Richard Henderson 6597c28d61 target/openrisc: Optimize for r0 being zero
The HW does not special-case r0, but the ABI specifies that r0 should
contain 0.  If we expose this fact to the optimizer, we can simplify
a lot of the generated code.  We must of course verify that r0==0, but
that is trivial to do with a TB flag.

Signed-off-by: Richard Henderson <rth@twiddle.net>
2017-02-14 08:15:00 +11:00

63 lines
1.6 KiB
C

/*
* OpenRISC exception helper routines
*
* Copyright (c) 2011-2012 Jia Liu <proljc@gmail.com>
*
* 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 "qemu/osdep.h"
#include "cpu.h"
#include "exec/exec-all.h"
#include "exec/helper-proto.h"
#include "exec/exec-all.h"
#include "exception.h"
void HELPER(exception)(CPUOpenRISCState *env, uint32_t excp)
{
OpenRISCCPU *cpu = openrisc_env_get_cpu(env);
raise_exception(cpu, excp);
}
static void QEMU_NORETURN do_range(CPUOpenRISCState *env, uintptr_t pc)
{
OpenRISCCPU *cpu = openrisc_env_get_cpu(env);
CPUState *cs = CPU(cpu);
cs->exception_index = EXCP_RANGE;
cpu_loop_exit_restore(cs, pc);
}
void HELPER(ove_cy)(CPUOpenRISCState *env)
{
if (env->sr_cy) {
do_range(env, GETPC());
}
}
void HELPER(ove_ov)(CPUOpenRISCState *env)
{
if (env->sr_ov < 0) {
do_range(env, GETPC());
}
}
void HELPER(ove_cyov)(CPUOpenRISCState *env)
{
if (env->sr_cy || env->sr_ov < 0) {
do_range(env, GETPC());
}
}