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/* Lattice Mico32 exception and system call support.
Contributed by Jon Beniston <jon@beniston.com>
Copyright (C) 2009-2015 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#define WANT_CPU lm32bf
#define WANT_CPU_LM32BF
#include "sim-main.h"
#include "lm32-sim.h"
#include "targ-vals.h"
/* Read memory function for system call interface. */
static int
syscall_read_mem (host_callback * cb, struct cb_syscall *sc,
unsigned long taddr, char *buf, int bytes)
{
SIM_DESC sd = (SIM_DESC) sc->p1;
SIM_CPU *cpu = (SIM_CPU *) sc->p2;
return sim_core_read_buffer (sd, cpu, read_map, buf, taddr, bytes);
}
/* Write memory function for system call interface. */
static int
syscall_write_mem (host_callback * cb, struct cb_syscall *sc,
unsigned long taddr, const char *buf, int bytes)
{
SIM_DESC sd = (SIM_DESC) sc->p1;
SIM_CPU *cpu = (SIM_CPU *) sc->p2;
return sim_core_write_buffer (sd, cpu, write_map, buf, taddr, bytes);
}
/* Handle invalid instructions. */
SEM_PC
sim_engine_invalid_insn (SIM_CPU * current_cpu, IADDR cia, SEM_PC pc)
{
SIM_DESC sd = CPU_STATE (current_cpu);
sim_engine_halt (sd, current_cpu, NULL, cia, sim_stopped, SIM_SIGILL);
return pc;
}
/* Handle divide instructions. */
USI
lm32bf_divu_insn (SIM_CPU * current_cpu, IADDR pc, USI r0, USI r1, USI r2)
{
SIM_DESC sd = CPU_STATE (current_cpu);
host_callback *cb = STATE_CALLBACK (sd);
/* Check for divide by zero */
if (GET_H_GR (r1) == 0)
{
if (STATE_ENVIRONMENT (sd) != OPERATING_ENVIRONMENT)
sim_engine_halt (sd, current_cpu, NULL, pc, sim_stopped, SIM_SIGFPE);
else
{
/* Save PC in exception address register. */
SET_H_GR (30, pc);
/* Save and clear interrupt enable. */
SET_H_CSR (LM32_CSR_IE, (GET_H_CSR (LM32_CSR_IE) & 1) << 1);
/* Branch to divide by zero exception handler. */
return GET_H_CSR (LM32_CSR_EBA) + LM32_EID_DIVIDE_BY_ZERO * 32;
}
}
else
{
SET_H_GR (r2, (USI) GET_H_GR (r0) / (USI) GET_H_GR (r1));
return pc + 4;
}
}
USI
lm32bf_modu_insn (SIM_CPU * current_cpu, IADDR pc, USI r0, USI r1, USI r2)
{
SIM_DESC sd = CPU_STATE (current_cpu);
host_callback *cb = STATE_CALLBACK (sd);
/* Check for divide by zero. */
if (GET_H_GR (r1) == 0)
{
if (STATE_ENVIRONMENT (sd) != OPERATING_ENVIRONMENT)
sim_engine_halt (sd, current_cpu, NULL, pc, sim_stopped, SIM_SIGFPE);
else
{
/* Save PC in exception address register. */
SET_H_GR (30, pc);
/* Save and clear interrupt enable. */
SET_H_CSR (LM32_CSR_IE, (GET_H_CSR (LM32_CSR_IE) & 1) << 1);
/* Branch to divide by zero exception handler. */
return GET_H_CSR (LM32_CSR_EBA) + LM32_EID_DIVIDE_BY_ZERO * 32;
}
}
else
{
SET_H_GR (r2, (USI) GET_H_GR (r0) % (USI) GET_H_GR (r1));
return pc + 4;
}
}
/* Handle break instructions. */
USI
lm32bf_break_insn (SIM_CPU * current_cpu, IADDR pc)
{
SIM_DESC sd = CPU_STATE (current_cpu);
host_callback *cb = STATE_CALLBACK (sd);
/* Breakpoint. */
if (STATE_ENVIRONMENT (sd) != OPERATING_ENVIRONMENT)
{
sim_engine_halt (sd, current_cpu, NULL, pc, sim_stopped, SIM_SIGTRAP);
return pc;
}
else
{
/* Save PC in breakpoint address register. */
SET_H_GR (31, pc);
/* Save and clear interrupt enable. */
SET_H_CSR (LM32_CSR_IE, (GET_H_CSR (LM32_CSR_IE) & 1) << 2);
/* Branch to breakpoint exception handler. */
return GET_H_CSR (LM32_CSR_DEBA) + LM32_EID_BREAKPOINT * 32;
}
}
/* Handle scall instructions. */
USI
lm32bf_scall_insn (SIM_CPU * current_cpu, IADDR pc)
{
SIM_DESC sd = CPU_STATE (current_cpu);
host_callback *cb = STATE_CALLBACK (sd);
if ((STATE_ENVIRONMENT (sd) != OPERATING_ENVIRONMENT)
|| (GET_H_GR (8) == TARGET_SYS_exit))
{
/* Delegate system call to host O/S. */
CB_SYSCALL s;
CB_SYSCALL_INIT (&s);
s.p1 = (PTR) sd;
s.p2 = (PTR) current_cpu;
s.read_mem = syscall_read_mem;
s.write_mem = syscall_write_mem;
/* Extract parameters. */
s.func = GET_H_GR (8);
s.arg1 = GET_H_GR (1);
s.arg2 = GET_H_GR (2);
s.arg3 = GET_H_GR (3);
/* Halt the simulator if the requested system call is _exit. */
if (s.func == TARGET_SYS_exit)
sim_engine_halt (sd, current_cpu, NULL, pc, sim_exited, s.arg1);
/* Perform the system call. */
cb_syscall (cb, &s);
/* Store the return value in the CPU's registers. */
SET_H_GR (1, s.result);
SET_H_GR (2, s.result2);
SET_H_GR (3, s.errcode);
/* Skip over scall instruction. */
return pc + 4;
}
else
{
/* Save PC in exception address register. */
SET_H_GR (30, pc);
/* Save and clear interrupt enable */
SET_H_CSR (LM32_CSR_IE, (GET_H_CSR (LM32_CSR_IE) & 1) << 1);
/* Branch to system call exception handler. */
return GET_H_CSR (LM32_CSR_EBA) + LM32_EID_SYSTEM_CALL * 32;
}
}
/* Handle b instructions. */
USI
lm32bf_b_insn (SIM_CPU * current_cpu, USI r0, USI f_r0)
{
SIM_DESC sd = CPU_STATE (current_cpu);
host_callback *cb = STATE_CALLBACK (sd);
/* Restore interrupt enable. */
if (f_r0 == 30)
SET_H_CSR (LM32_CSR_IE, (GET_H_CSR (LM32_CSR_IE) & 2) >> 1);
else if (f_r0 == 31)
SET_H_CSR (LM32_CSR_IE, (GET_H_CSR (LM32_CSR_IE) & 4) >> 2);
return r0;
}
/* Handle wcsr instructions. */
void
lm32bf_wcsr_insn (SIM_CPU * current_cpu, USI f_csr, USI r1)
{
SIM_DESC sd = CPU_STATE (current_cpu);
host_callback *cb = STATE_CALLBACK (sd);
/* Writing a 1 to IP CSR clears a bit, writing 0 has no effect. */
if (f_csr == LM32_CSR_IP)
SET_H_CSR (f_csr, GET_H_CSR (f_csr) & ~r1);
else
SET_H_CSR (f_csr, r1);
}
/* Handle signals. */
void
lm32_core_signal (SIM_DESC sd,
sim_cpu * cpu,
sim_cia cia,
unsigned map,
int nr_bytes,
address_word addr,
transfer_type transfer, sim_core_signals sig)
{
const char *copy = (transfer == read_transfer ? "read" : "write");
address_word ip = CIA_ADDR (cia);
SIM_CPU *current_cpu = cpu;
switch (sig)
{
case sim_core_unmapped_signal:
sim_io_eprintf (sd,
"core: %d byte %s to unmapped address 0x%lx at 0x%lx\n",
nr_bytes, copy, (unsigned long) addr,
(unsigned long) ip);
SET_H_GR (30, ip);
/* Save and clear interrupt enable. */
SET_H_CSR (LM32_CSR_IE, (GET_H_CSR (LM32_CSR_IE) & 1) << 1);
CPU_PC_SET (cpu, GET_H_CSR (LM32_CSR_EBA) + LM32_EID_DATA_BUS_ERROR * 32);
sim_engine_halt (sd, cpu, NULL, LM32_EID_DATA_BUS_ERROR * 32,
sim_stopped, SIM_SIGSEGV);
break;
case sim_core_unaligned_signal:
sim_io_eprintf (sd,
"core: %d byte misaligned %s to address 0x%lx at 0x%lx\n",
nr_bytes, copy, (unsigned long) addr,
(unsigned long) ip);
SET_H_GR (30, ip);
/* Save and clear interrupt enable. */
SET_H_CSR (LM32_CSR_IE, (GET_H_CSR (LM32_CSR_IE) & 1) << 1);
CPU_PC_SET (cpu, GET_H_CSR (LM32_CSR_EBA) + LM32_EID_DATA_BUS_ERROR * 32);
sim_engine_halt (sd, cpu, NULL, LM32_EID_DATA_BUS_ERROR * 32,
sim_stopped, SIM_SIGBUS);
break;
default:
sim_engine_abort (sd, cpu, cia,
"sim_core_signal - internal error - bad switch");
}
}
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