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/*
* M68K helper routines
*
* Copyright (c) 2007 CodeSourcery
*
* 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 "cpu.h"
#include "exec/helper-proto.h"
#include "exec/cpu_ldst.h"
#if defined(CONFIG_USER_ONLY)
void m68k_cpu_do_interrupt(CPUState *cs)
{
cs->exception_index = -1;
}
static inline void do_interrupt_m68k_hardirq(CPUM68KState *env)
{
}
#else
extern int semihosting_enabled;
/* Try to fill the TLB and return an exception if error. If retaddr is
NULL, it means that the function was called in C code (i.e. not
from generated code or from helper.c) */
void tlb_fill(CPUState *cs, target_ulong addr, int is_write, int mmu_idx,
uintptr_t retaddr)
{
int ret;
ret = m68k_cpu_handle_mmu_fault(cs, addr, is_write, mmu_idx);
if (unlikely(ret)) {
if (retaddr) {
/* now we have a real cpu fault */
cpu_restore_state(cs, retaddr);
}
cpu_loop_exit(cs);
}
}
static void do_rte(CPUM68KState *env)
{
uint32_t sp;
uint32_t fmt;
sp = env->aregs[7];
fmt = cpu_ldl_kernel(env, sp);
env->pc = cpu_ldl_kernel(env, sp + 4);
sp |= (fmt >> 28) & 3;
env->sr = fmt & 0xffff;
m68k_switch_sp(env);
env->aregs[7] = sp + 8;
}
static void do_interrupt_all(CPUM68KState *env, int is_hw)
{
CPUState *cs = CPU(m68k_env_get_cpu(env));
uint32_t sp;
uint32_t fmt;
uint32_t retaddr;
uint32_t vector;
fmt = 0;
retaddr = env->pc;
if (!is_hw) {
switch (cs->exception_index) {
case EXCP_RTE:
/* Return from an exception. */
do_rte(env);
return;
case EXCP_HALT_INSN:
if (semihosting_enabled
&& (env->sr & SR_S) != 0
&& (env->pc & 3) == 0
&& cpu_lduw_code(env, env->pc - 4) == 0x4e71
&& cpu_ldl_code(env, env->pc) == 0x4e7bf000) {
env->pc += 4;
do_m68k_semihosting(env, env->dregs[0]);
return;
}
cs->halted = 1;
cs->exception_index = EXCP_HLT;
cpu_loop_exit(cs);
return;
}
if (cs->exception_index >= EXCP_TRAP0
&& cs->exception_index <= EXCP_TRAP15) {
/* Move the PC after the trap instruction. */
retaddr += 2;
}
}
vector = cs->exception_index << 2;
sp = env->aregs[7];
fmt |= 0x40000000;
fmt |= (sp & 3) << 28;
fmt |= vector << 16;
fmt |= env->sr;
env->sr |= SR_S;
if (is_hw) {
env->sr = (env->sr & ~SR_I) | (env->pending_level << SR_I_SHIFT);
env->sr &= ~SR_M;
}
m68k_switch_sp(env);
/* ??? This could cause MMU faults. */
sp &= ~3;
sp -= 4;
cpu_stl_kernel(env, sp, retaddr);
sp -= 4;
cpu_stl_kernel(env, sp, fmt);
env->aregs[7] = sp;
/* Jump to vector. */
env->pc = cpu_ldl_kernel(env, env->vbr + vector);
}
void m68k_cpu_do_interrupt(CPUState *cs)
{
M68kCPU *cpu = M68K_CPU(cs);
CPUM68KState *env = &cpu->env;
do_interrupt_all(env, 0);
}
static inline void do_interrupt_m68k_hardirq(CPUM68KState *env)
{
do_interrupt_all(env, 1);
}
#endif
bool m68k_cpu_exec_interrupt(CPUState *cs, int interrupt_request)
{
M68kCPU *cpu = M68K_CPU(cs);
CPUM68KState *env = &cpu->env;
if (interrupt_request & CPU_INTERRUPT_HARD
&& ((env->sr & SR_I) >> SR_I_SHIFT) < env->pending_level) {
/* Real hardware gets the interrupt vector via an IACK cycle
at this point. Current emulated hardware doesn't rely on
this, so we provide/save the vector when the interrupt is
first signalled. */
cs->exception_index = env->pending_vector;
do_interrupt_m68k_hardirq(env);
return true;
}
return false;
}
static void raise_exception(CPUM68KState *env, int tt)
{
CPUState *cs = CPU(m68k_env_get_cpu(env));
cs->exception_index = tt;
cpu_loop_exit(cs);
}
void HELPER(raise_exception)(CPUM68KState *env, uint32_t tt)
{
raise_exception(env, tt);
}
void HELPER(divu)(CPUM68KState *env, uint32_t word)
{
uint32_t num;
uint32_t den;
uint32_t quot;
uint32_t rem;
uint32_t flags;
num = env->div1;
den = env->div2;
/* ??? This needs to make sure the throwing location is accurate. */
if (den == 0) {
raise_exception(env, EXCP_DIV0);
}
quot = num / den;
rem = num % den;
flags = 0;
if (word && quot > 0xffff)
flags |= CCF_V;
if (quot == 0)
flags |= CCF_Z;
else if ((int32_t)quot < 0)
flags |= CCF_N;
env->div1 = quot;
env->div2 = rem;
env->cc_dest = flags;
}
void HELPER(divs)(CPUM68KState *env, uint32_t word)
{
int32_t num;
int32_t den;
int32_t quot;
int32_t rem;
int32_t flags;
num = env->div1;
den = env->div2;
if (den == 0) {
raise_exception(env, EXCP_DIV0);
}
quot = num / den;
rem = num % den;
flags = 0;
if (word && quot != (int16_t)quot)
flags |= CCF_V;
if (quot == 0)
flags |= CCF_Z;
else if (quot < 0)
flags |= CCF_N;
env->div1 = quot;
env->div2 = rem;
env->cc_dest = flags;
}
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