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121 lines
3.5 KiB
C
121 lines
3.5 KiB
C
/*
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* Altera Nios II helper routines.
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*
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* Copyright (C) 2012 Chris Wulff <crwulff@gmail.com>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, see
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* <http://www.gnu.org/licenses/lgpl-2.1.html>
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*/
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#include "qemu/osdep.h"
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#include "cpu.h"
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#include "exec/helper-proto.h"
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#include "exec/exec-all.h"
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#include "qemu/main-loop.h"
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void helper_raise_exception(CPUNios2State *env, uint32_t index)
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{
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CPUState *cs = env_cpu(env);
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cs->exception_index = index;
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cpu_loop_exit(cs);
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}
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void nios2_cpu_loop_exit_advance(CPUNios2State *env, uintptr_t retaddr)
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{
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CPUState *cs = env_cpu(env);
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/*
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* Note that PC is advanced for all hardware exceptions.
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* Do this here, rather than in restore_state_to_opc(),
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* lest we affect QEMU internal exceptions, like EXCP_DEBUG.
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*/
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cpu_restore_state(cs, retaddr);
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env->pc += 4;
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cpu_loop_exit(cs);
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}
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static void maybe_raise_div(CPUNios2State *env, uintptr_t ra)
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{
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Nios2CPU *cpu = env_archcpu(env);
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CPUState *cs = env_cpu(env);
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if (cpu->diverr_present) {
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cs->exception_index = EXCP_DIV;
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nios2_cpu_loop_exit_advance(env, ra);
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}
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}
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int32_t helper_divs(CPUNios2State *env, int32_t num, int32_t den)
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{
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if (unlikely(den == 0) || unlikely(den == -1 && num == INT32_MIN)) {
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maybe_raise_div(env, GETPC());
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return num; /* undefined */
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}
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return num / den;
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}
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uint32_t helper_divu(CPUNios2State *env, uint32_t num, uint32_t den)
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{
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if (unlikely(den == 0)) {
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maybe_raise_div(env, GETPC());
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return num; /* undefined */
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}
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return num / den;
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}
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#ifndef CONFIG_USER_ONLY
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void helper_eret(CPUNios2State *env, uint32_t new_status, uint32_t new_pc)
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{
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Nios2CPU *cpu = env_archcpu(env);
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CPUState *cs = env_cpu(env);
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if (unlikely(new_pc & 3)) {
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env->ctrl[CR_BADADDR] = new_pc;
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cs->exception_index = EXCP_UNALIGND;
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nios2_cpu_loop_exit_advance(env, GETPC());
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}
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/*
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* None of estatus, bstatus, or sstatus have constraints on write;
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* do not allow reserved fields in status to be set.
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* When shadow registers are enabled, eret *does* restore CRS.
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* Rather than testing eic_present to decide, mask CRS out of
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* the set of readonly fields.
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*/
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new_status &= cpu->cr_state[CR_STATUS].writable |
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(cpu->cr_state[CR_STATUS].readonly & R_CR_STATUS_CRS_MASK);
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env->ctrl[CR_STATUS] = new_status;
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env->pc = new_pc;
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nios2_update_crs(env);
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cpu_loop_exit(cs);
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}
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/*
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* RDPRS and WRPRS are implemented out of line so that if PRS == CRS,
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* all of the tcg global temporaries are synced back to ENV.
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*/
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uint32_t helper_rdprs(CPUNios2State *env, uint32_t regno)
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{
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unsigned prs = FIELD_EX32(env->ctrl[CR_STATUS], CR_STATUS, PRS);
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return env->shadow_regs[prs][regno];
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}
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void helper_wrprs(CPUNios2State *env, uint32_t regno, uint32_t val)
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{
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unsigned prs = FIELD_EX32(env->ctrl[CR_STATUS], CR_STATUS, PRS);
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env->shadow_regs[prs][regno] = val;
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}
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#endif /* !CONFIG_USER_ONLY */
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