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/*
* 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);
}
void nios2_cpu_loop_exit_advance(CPUNios2State *env, uintptr_t retaddr)
{
CPUState *cs = env_cpu(env);
/*
* Note that PC is advanced for all hardware exceptions.
* Do this here, rather than in restore_state_to_opc(),
* lest we affect QEMU internal exceptions, like EXCP_DEBUG.
*/
cpu_restore_state(cs, retaddr, true);
env->pc += 4;
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;
nios2_cpu_loop_exit_advance(env, 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);
CPUState *cs = env_cpu(env);
if (unlikely(new_pc & 3)) {
env->ctrl[CR_BADADDR] = new_pc;
cs->exception_index = EXCP_UNALIGND;
nios2_cpu_loop_exit_advance(env, GETPC());
}
/*
* None of estatus, bstatus, or sstatus have constraints on write;
* do not allow reserved fields in status to be set.
* When shadow registers are enabled, eret *does* restore CRS.
* Rather than testing eic_present to decide, mask CRS out of
* the set of readonly fields.
*/
new_status &= cpu->cr_state[CR_STATUS].writable |
(cpu->cr_state[CR_STATUS].readonly & R_CR_STATUS_CRS_MASK);
env->ctrl[CR_STATUS] = new_status;
env->pc = new_pc;
nios2_update_crs(env);
cpu_loop_exit(cs);
}
/*
* RDPRS and WRPRS are implemented out of line so that if PRS == CRS,
* all of the tcg global temporaries are synced back to ENV.
*/
uint32_t helper_rdprs(CPUNios2State *env, uint32_t regno)
{
unsigned prs = FIELD_EX32(env->ctrl[CR_STATUS], CR_STATUS, PRS);
return env->shadow_regs[prs][regno];
}
void helper_wrprs(CPUNios2State *env, uint32_t regno, uint32_t val)
{
unsigned prs = FIELD_EX32(env->ctrl[CR_STATUS], CR_STATUS, PRS);
env->shadow_regs[prs][regno] = val;
}
#endif /* !CONFIG_USER_ONLY */
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