f59df3f235
Several of the system registers handled via the ARMCPRegInfo mechanism have access trap control bits controlling whether the registers are accessible to lower privilege levels. Replace the existing mechanism (allowing the read and write functions to return EXCP_UDEF if access is denied) with a dedicated "check access rights" function pointer in the ARMCPRegInfo. This will allow us to simplify some of the register definitions, which no longer need read/write functions purely to handle the access checks. We take the opportunity to define the return value from the access checking function in a way that allows us to set the correct exception syndrome information for exceptions taken to AArch64 (which may need to distinguish access failures due to a configurable trap or enable from other kinds of access failure). This commit defines the new mechanism but does not move any of the registers across to use it. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
399 lines
9.4 KiB
C
399 lines
9.4 KiB
C
/*
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* ARM helper routines
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*
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* Copyright (c) 2005-2007 CodeSourcery, LLC
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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 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 <http://www.gnu.org/licenses/>.
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*/
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#include "cpu.h"
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#include "helper.h"
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#define SIGNBIT (uint32_t)0x80000000
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#define SIGNBIT64 ((uint64_t)1 << 63)
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static void raise_exception(CPUARMState *env, int tt)
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{
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env->exception_index = tt;
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cpu_loop_exit(env);
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}
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uint32_t HELPER(neon_tbl)(CPUARMState *env, uint32_t ireg, uint32_t def,
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uint32_t rn, uint32_t maxindex)
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{
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uint32_t val;
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uint32_t tmp;
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int index;
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int shift;
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uint64_t *table;
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table = (uint64_t *)&env->vfp.regs[rn];
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val = 0;
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for (shift = 0; shift < 32; shift += 8) {
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index = (ireg >> shift) & 0xff;
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if (index < maxindex) {
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tmp = (table[index >> 3] >> ((index & 7) << 3)) & 0xff;
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val |= tmp << shift;
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} else {
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val |= def & (0xff << shift);
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}
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}
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return val;
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}
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#if !defined(CONFIG_USER_ONLY)
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#include "exec/softmmu_exec.h"
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#define MMUSUFFIX _mmu
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#define SHIFT 0
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#include "exec/softmmu_template.h"
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#define SHIFT 1
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#include "exec/softmmu_template.h"
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#define SHIFT 2
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#include "exec/softmmu_template.h"
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#define SHIFT 3
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#include "exec/softmmu_template.h"
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/* try to fill the TLB and return an exception if error. If retaddr is
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NULL, it means that the function was called in C code (i.e. not
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from generated code or from helper.c) */
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void tlb_fill(CPUARMState *env, target_ulong addr, int is_write, int mmu_idx,
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uintptr_t retaddr)
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{
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int ret;
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ret = cpu_arm_handle_mmu_fault(env, addr, is_write, mmu_idx);
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if (unlikely(ret)) {
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if (retaddr) {
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/* now we have a real cpu fault */
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cpu_restore_state(env, retaddr);
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}
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raise_exception(env, env->exception_index);
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}
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}
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#endif
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uint32_t HELPER(add_setq)(CPUARMState *env, uint32_t a, uint32_t b)
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{
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uint32_t res = a + b;
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if (((res ^ a) & SIGNBIT) && !((a ^ b) & SIGNBIT))
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env->QF = 1;
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return res;
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}
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uint32_t HELPER(add_saturate)(CPUARMState *env, uint32_t a, uint32_t b)
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{
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uint32_t res = a + b;
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if (((res ^ a) & SIGNBIT) && !((a ^ b) & SIGNBIT)) {
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env->QF = 1;
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res = ~(((int32_t)a >> 31) ^ SIGNBIT);
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}
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return res;
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}
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uint32_t HELPER(sub_saturate)(CPUARMState *env, uint32_t a, uint32_t b)
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{
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uint32_t res = a - b;
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if (((res ^ a) & SIGNBIT) && ((a ^ b) & SIGNBIT)) {
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env->QF = 1;
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res = ~(((int32_t)a >> 31) ^ SIGNBIT);
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}
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return res;
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}
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uint32_t HELPER(double_saturate)(CPUARMState *env, int32_t val)
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{
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uint32_t res;
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if (val >= 0x40000000) {
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res = ~SIGNBIT;
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env->QF = 1;
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} else if (val <= (int32_t)0xc0000000) {
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res = SIGNBIT;
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env->QF = 1;
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} else {
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res = val << 1;
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}
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return res;
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}
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uint32_t HELPER(add_usaturate)(CPUARMState *env, uint32_t a, uint32_t b)
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{
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uint32_t res = a + b;
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if (res < a) {
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env->QF = 1;
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res = ~0;
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}
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return res;
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}
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uint32_t HELPER(sub_usaturate)(CPUARMState *env, uint32_t a, uint32_t b)
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{
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uint32_t res = a - b;
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if (res > a) {
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env->QF = 1;
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res = 0;
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}
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return res;
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}
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/* Signed saturation. */
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static inline uint32_t do_ssat(CPUARMState *env, int32_t val, int shift)
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{
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int32_t top;
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uint32_t mask;
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top = val >> shift;
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mask = (1u << shift) - 1;
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if (top > 0) {
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env->QF = 1;
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return mask;
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} else if (top < -1) {
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env->QF = 1;
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return ~mask;
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}
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return val;
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}
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/* Unsigned saturation. */
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static inline uint32_t do_usat(CPUARMState *env, int32_t val, int shift)
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{
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uint32_t max;
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max = (1u << shift) - 1;
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if (val < 0) {
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env->QF = 1;
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return 0;
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} else if (val > max) {
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env->QF = 1;
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return max;
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}
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return val;
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}
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/* Signed saturate. */
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uint32_t HELPER(ssat)(CPUARMState *env, uint32_t x, uint32_t shift)
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{
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return do_ssat(env, x, shift);
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}
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/* Dual halfword signed saturate. */
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uint32_t HELPER(ssat16)(CPUARMState *env, uint32_t x, uint32_t shift)
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{
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uint32_t res;
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res = (uint16_t)do_ssat(env, (int16_t)x, shift);
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res |= do_ssat(env, ((int32_t)x) >> 16, shift) << 16;
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return res;
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}
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/* Unsigned saturate. */
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uint32_t HELPER(usat)(CPUARMState *env, uint32_t x, uint32_t shift)
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{
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return do_usat(env, x, shift);
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}
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/* Dual halfword unsigned saturate. */
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uint32_t HELPER(usat16)(CPUARMState *env, uint32_t x, uint32_t shift)
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{
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uint32_t res;
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res = (uint16_t)do_usat(env, (int16_t)x, shift);
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res |= do_usat(env, ((int32_t)x) >> 16, shift) << 16;
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return res;
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}
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void HELPER(wfi)(CPUARMState *env)
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{
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CPUState *cs = CPU(arm_env_get_cpu(env));
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env->exception_index = EXCP_HLT;
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cs->halted = 1;
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cpu_loop_exit(env);
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}
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void HELPER(exception)(CPUARMState *env, uint32_t excp)
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{
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env->exception_index = excp;
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cpu_loop_exit(env);
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}
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uint32_t HELPER(cpsr_read)(CPUARMState *env)
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{
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return cpsr_read(env) & ~CPSR_EXEC;
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}
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void HELPER(cpsr_write)(CPUARMState *env, uint32_t val, uint32_t mask)
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{
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cpsr_write(env, val, mask);
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}
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/* Access to user mode registers from privileged modes. */
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uint32_t HELPER(get_user_reg)(CPUARMState *env, uint32_t regno)
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{
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uint32_t val;
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if (regno == 13) {
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val = env->banked_r13[0];
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} else if (regno == 14) {
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val = env->banked_r14[0];
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} else if (regno >= 8
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&& (env->uncached_cpsr & 0x1f) == ARM_CPU_MODE_FIQ) {
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val = env->usr_regs[regno - 8];
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} else {
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val = env->regs[regno];
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}
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return val;
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}
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void HELPER(set_user_reg)(CPUARMState *env, uint32_t regno, uint32_t val)
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{
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if (regno == 13) {
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env->banked_r13[0] = val;
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} else if (regno == 14) {
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env->banked_r14[0] = val;
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} else if (regno >= 8
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&& (env->uncached_cpsr & 0x1f) == ARM_CPU_MODE_FIQ) {
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env->usr_regs[regno - 8] = val;
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} else {
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env->regs[regno] = val;
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}
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}
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void HELPER(access_check_cp_reg)(CPUARMState *env, void *rip)
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{
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const ARMCPRegInfo *ri = rip;
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switch (ri->accessfn(env, ri)) {
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case CP_ACCESS_OK:
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return;
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case CP_ACCESS_TRAP:
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case CP_ACCESS_TRAP_UNCATEGORIZED:
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/* These cases will eventually need to generate different
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* syndrome information.
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*/
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break;
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default:
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g_assert_not_reached();
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}
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raise_exception(env, EXCP_UDEF);
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}
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void HELPER(set_cp_reg)(CPUARMState *env, void *rip, uint32_t value)
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{
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const ARMCPRegInfo *ri = rip;
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int excp = ri->writefn(env, ri, value);
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if (excp) {
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raise_exception(env, excp);
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}
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}
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uint32_t HELPER(get_cp_reg)(CPUARMState *env, void *rip)
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{
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const ARMCPRegInfo *ri = rip;
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uint64_t value;
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int excp = ri->readfn(env, ri, &value);
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if (excp) {
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raise_exception(env, excp);
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}
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return value;
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}
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void HELPER(set_cp_reg64)(CPUARMState *env, void *rip, uint64_t value)
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{
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const ARMCPRegInfo *ri = rip;
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int excp = ri->writefn(env, ri, value);
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if (excp) {
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raise_exception(env, excp);
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}
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}
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uint64_t HELPER(get_cp_reg64)(CPUARMState *env, void *rip)
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{
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const ARMCPRegInfo *ri = rip;
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uint64_t value;
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int excp = ri->readfn(env, ri, &value);
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if (excp) {
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raise_exception(env, excp);
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}
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return value;
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}
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/* ??? Flag setting arithmetic is awkward because we need to do comparisons.
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The only way to do that in TCG is a conditional branch, which clobbers
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all our temporaries. For now implement these as helper functions. */
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/* Similarly for variable shift instructions. */
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uint32_t HELPER(shl_cc)(CPUARMState *env, uint32_t x, uint32_t i)
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{
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int shift = i & 0xff;
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if (shift >= 32) {
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if (shift == 32)
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env->CF = x & 1;
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else
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env->CF = 0;
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return 0;
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} else if (shift != 0) {
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env->CF = (x >> (32 - shift)) & 1;
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return x << shift;
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}
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return x;
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}
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uint32_t HELPER(shr_cc)(CPUARMState *env, uint32_t x, uint32_t i)
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{
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int shift = i & 0xff;
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if (shift >= 32) {
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if (shift == 32)
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env->CF = (x >> 31) & 1;
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else
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env->CF = 0;
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return 0;
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} else if (shift != 0) {
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env->CF = (x >> (shift - 1)) & 1;
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return x >> shift;
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}
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return x;
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}
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uint32_t HELPER(sar_cc)(CPUARMState *env, uint32_t x, uint32_t i)
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{
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int shift = i & 0xff;
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if (shift >= 32) {
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env->CF = (x >> 31) & 1;
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return (int32_t)x >> 31;
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} else if (shift != 0) {
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env->CF = (x >> (shift - 1)) & 1;
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return (int32_t)x >> shift;
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}
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return x;
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}
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uint32_t HELPER(ror_cc)(CPUARMState *env, uint32_t x, uint32_t i)
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{
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int shift1, shift;
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shift1 = i & 0xff;
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shift = shift1 & 0x1f;
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if (shift == 0) {
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if (shift1 != 0)
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env->CF = (x >> 31) & 1;
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return x;
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} else {
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env->CF = (x >> (shift - 1)) & 1;
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return ((uint32_t)x >> shift) | (x << (32 - shift));
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}
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}
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