qemu/target/nios2/op_helper.c
Richard Henderson 345b7a8757 target/nios2: Support division error exception
Division may (optionally) raise a division exception.
Since the linux kernel has been prepared for this for
some time, enable it by default.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220421151735.31996-42-richard.henderson@linaro.org>
2022-04-26 08:16:41 -07:00

80 lines
2.2 KiB
C

/*
* Altera Nios II helper routines.
*
* Copyright (C) 2012 Chris Wulff <crwulff@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 2.1 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/lgpl-2.1.html>
*/
#include "qemu/osdep.h"
#include "cpu.h"
#include "exec/helper-proto.h"
#include "exec/exec-all.h"
#include "qemu/main-loop.h"
void helper_raise_exception(CPUNios2State *env, uint32_t index)
{
CPUState *cs = env_cpu(env);
cs->exception_index = index;
cpu_loop_exit(cs);
}
static void maybe_raise_div(CPUNios2State *env, uintptr_t ra)
{
Nios2CPU *cpu = env_archcpu(env);
CPUState *cs = env_cpu(env);
if (cpu->diverr_present) {
cs->exception_index = EXCP_DIV;
cpu_loop_exit_restore(cs, ra);
}
}
int32_t helper_divs(CPUNios2State *env, int32_t num, int32_t den)
{
if (unlikely(den == 0) || unlikely(den == -1 && num == INT32_MIN)) {
maybe_raise_div(env, GETPC());
return num; /* undefined */
}
return num / den;
}
uint32_t helper_divu(CPUNios2State *env, uint32_t num, uint32_t den)
{
if (unlikely(den == 0)) {
maybe_raise_div(env, GETPC());
return num; /* undefined */
}
return num / den;
}
#ifndef CONFIG_USER_ONLY
void helper_eret(CPUNios2State *env, uint32_t new_status, uint32_t new_pc)
{
Nios2CPU *cpu = env_archcpu(env);
/*
* Both estatus and bstatus have no constraints on write;
* do not allow reserved fields in status to be set.
* TODO: more than this is required for shadow registers.
*/
new_status &= cpu->cr_state[CR_STATUS].writable;
env->ctrl[CR_STATUS] = new_status;
env->pc = new_pc;
cpu_loop_exit(env_cpu(env));
}
#endif /* !CONFIG_USER_ONLY */