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machine.c
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machine.c
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/*
The XSM machine simulator.
*/
#include "machine.h"
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
static xsm_cpu _thecpu;
static xsm_options _theoptions;
const char *instructions[] = {
"MOV",
"ADD",
"SUB",
"MUL",
"DIV",
"MOD",
"INR",
"DCR",
"LT",
"GT",
"EQ",
"NE",
"GE",
"LE",
"JZ",
"JNZ",
"JMP",
"PUSH",
"POP",
"CALL",
"RET",
"BRKP",
"INT",
"LOADI",
"LOAD",
"STORE",
"ENCRYPT",
"BACKUP",
"RESTORE",
"PORT",
"IN",
"INI",
"OUT",
"IRET",
"START",
"RESET",
"TSL",
"HALT",
"NOP"};
/* Initialise the XSM machine */
int machine_init(xsm_options *options)
{
xsm_word *ipreg, *core_flag;
_theoptions = *options;
if (!registers_init())
return XSM_FAILURE;
if (!memory_init())
return XSM_FAILURE;
if (!debug_init())
return FALSE;
/* Storing ROM code */
word_store_string(memory_get_word(0), "LOADI 1, 0");
word_store_string(memory_get_word(2), "JMP 512");
/* Set up IP */
ipreg = machine_get_ipreg(PRIMARY_CORE);
word_store_integer(ipreg, 0);
/* Set up CORE flag */
core_flag = registers_get_register("CORE", PRIMARY_CORE);
word_store_integer(core_flag, PRIMARY_CORE);
core_flag = registers_get_register("CORE", SECONDARY_CORE);
word_store_integer(core_flag, SECONDARY_CORE);
/* Set up the primary core */
machine_set_core(PRIMARY_CORE);
/* Set the mode */
machine_set_mode(PRIVILEGE_KERNEL);
/* The disk and console is idle.*/
_thecpu.console_state = XSM_CONSOLE_IDLE;
_thecpu.disk_state = XSM_DISK_IDLE;
/* Initialise timer clock*/
_thecpu.timer[PRIMARY_CORE] = _theoptions.timer;
/* Reset the core state */
_thecpu.core_state = RESET_MODE;
return XSM_SUCCESS;
}
/* Initialise the secondary core */
int machine_init_dual()
{
xsm_word *ipreg, *core_flag;
/* Set up IP */
ipreg = registers_get_register("IP", SECONDARY_CORE);
word_store_integer(ipreg, DUAL_BOOTSTRAP);
/* Set the mode */
_thecpu.mode[SECONDARY_CORE] = PRIVILEGE_KERNEL;
/* Initialise timer clock*/
_thecpu.timer[SECONDARY_CORE] = _theoptions.timer;
/* Reset the mode for secondary core */
machine_set_core_state(ACTIVE_MODE);
return XSM_SUCCESS;
}
/* Retrieve the opcode */
int machine_get_opcode(const char *instr)
{
int i;
for (i = 0; i < XSM_INSTRUCTION_COUNT; ++i)
if (!strcasecmp(instr, instructions[i]))
return i;
return XSM_ILLINSTR;
}
/* Retieve the IP register */
xsm_word *machine_get_ipreg()
{
int core = machine_get_core();
return registers_get_register("IP", core);
}
/* Retrieve the SP register */
xsm_word *machine_get_spreg()
{
int core = machine_get_core();
return registers_get_register("SP", core);
}
/* Retrieve the given register */
xsm_word *machine_get_register(const char *name)
{
int mode, core;
xsm_word *reg;
core = machine_get_core();
mode = machine_get_mode();
reg = registers_get_register(name, core);
if (!reg)
machine_register_exception("No such register", EXP_ILLINSTR);
if (mode == PRIVILEGE_USER)
if (!registers_umode(name))
machine_register_exception("Register not available in USER mode", EXP_ILLINSTR);
if (!strcasecmp(name, "IP"))
machine_register_exception("IP register can not be directly manipulated", EXP_ILLINSTR);
if (!strcasecmp(name, "CORE"))
machine_register_exception("CORE flag can not be manipulated", EXP_ILLINSTR);
return reg;
}
/* Retrieve the given read-only register */
xsm_word *machine_read_register(const char *name)
{
int mode, core;
xsm_word *reg;
core = machine_get_core();
mode = machine_get_mode();
reg = registers_get_register(name, core);
if (!reg)
machine_register_exception("No such register", EXP_ILLINSTR);
if (mode == PRIVILEGE_USER)
if (!registers_umode(name))
machine_register_exception("Register not available in USER mode", EXP_ILLINSTR);
if (!strcasecmp(name, "IP"))
machine_register_exception("IP register can not be directly manipulated", EXP_ILLINSTR);
return reg;
}
/* Returns the opcode privilege */
int machine_instr_req_privilege(int opcode)
{
if (opcode >= TOKEN_KERN_LOW && opcode <= TOKEN_KERN_HIGH)
return PRIVILEGE_KERNEL;
return PRIVILEGE_USER;
}
/* An interface between lexer and machine */
int machine_serve_instruction(char *buffer, unsigned long *read_bytes, int max)
{
int ip_val, i, j, bytes_to_read, core;
xsm_word *ip_reg, *instr_mem;
bytes_to_read = XSM_INSTRUCTION_SIZE * XSM_WORD_SIZE;
core = machine_get_core();
ip_reg = machine_get_ipreg();
ip_val = word_get_integer(ip_reg);
ip_val = machine_translate_address(ip_val, FALSE, INSTR_FETCH, machine_get_core(), machine_get_mode());
instr_mem = machine_memory_get_word(ip_val);
memcpy(buffer, instr_mem->val, bytes_to_read);
if (strlen(buffer) == 0)
{
word_store_integer(machine_get_ipreg(), ip_val + XSM_INSTRUCTION_SIZE);
machine_register_exception("The simulator has encountered a NULL instruction", EXP_ILLINSTR);
}
/* Trim */
for (i = 0; i < bytes_to_read; i++)
if (buffer[i] == '\0')
for (j = i; j < bytes_to_read / 2; j++)
buffer[j] = ' ';
buffer[bytes_to_read - 1] = '\0';
*read_bytes = bytes_to_read;
return TRUE;
}
/* Start the XSM machine */
int machine_run()
{
int token, opcode, ipval, exp_occured, core;
YYSTYPE token_info;
xsm_word *ipreg;
while (TRUE)
{
/* Set the exception point */
exp_occured = setjmp(_thecpu.h_exp_point);
if (exp_occured == XSM_EXCEPTION_OCCURED)
{
if (machine_handle_exception() != XSM_SUCCESS)
break;
machine_change_core();
}
/* Flush the instruction stream */
tokenize_clear_stream();
tokenize_reset();
/* Pre-execute */
ipreg = machine_get_ipreg();
ipval = word_get_integer(ipreg);
machine_pre_execute(ipval);
token = tokenize_next_token(&token_info);
/* IP = IP + instruction length */
ipval = ipval + XSM_INSTRUCTION_SIZE;
word_store_integer(ipreg, ipval);
if (token != TOKEN_INSTRUCTION)
machine_register_exception("The simulator has encountered an illegal instruction", EXP_ILLINSTR);
opcode = machine_get_opcode(token_info.str);
if (opcode == XSM_ILLINSTR)
machine_register_exception("The instruction is not available in this architecture", EXP_ILLINSTR);
if (machine_instr_req_privilege(opcode) == PRIVILEGE_KERNEL && machine_get_mode() == PRIVILEGE_USER)
machine_register_exception("This instruction requires more privilege", EXP_ILLINSTR);
/* Stop the machine */
if (machine_execute_instruction(opcode) == XSM_HALT)
break;
/* Post-execute */
if (machine_get_mode() == PRIVILEGE_USER)
machine_post_execute();
machine_change_core();
}
return TRUE;
}
/* Changes the core in the machine */
void machine_change_core()
{
if (machine_get_core_state() == ACTIVE_MODE)
{
if (machine_get_core() == PRIMARY_CORE)
machine_set_core(SECONDARY_CORE);
else
machine_set_core(PRIMARY_CORE);
}
}
/* Set the exception values */
void machine_register_exception(char *message, int code)
{
int mode = machine_get_mode();
exception_set(message, code, mode);
/* Abandon ship! Abandon ship! */
longjmp(_thecpu.h_exp_point, XSM_EXCEPTION_OCCURED);
}
/* Handle the exception */
int machine_handle_exception()
{
int code, mode, core, curr_ip, num_regs, i;
char *message, *content;
const char **reg_names;
xsm_word *reg_eip, *reg_epn, *reg_ec, *reg_ema;
curr_ip = word_get_integer(machine_get_ipreg());
curr_ip = curr_ip - XSM_INSTRUCTION_SIZE;
word_store_integer(machine_get_ipreg(), curr_ip);
/* Get the details about the exception. */
core = machine_get_core();
mode = machine_get_mode();
code = exception_code();
message = exception_message();
/* Get the exception registers. */
reg_eip = registers_get_register("EIP", core);
reg_epn = registers_get_register("EPN", core);
reg_ec = registers_get_register("EC", core);
reg_ema = registers_get_register("EMA", core);
// Fetch IP stored in EIP
word_store_integer(reg_eip, curr_ip);
word_store_integer(reg_ec, code);
switch (code)
{
case EXP_ILLMEM:
word_store_integer(reg_ema, exception_get_ma());
word_store_string(reg_epn, "");
break;
case EXP_PAGEFAULT:
word_store_string(reg_ema, "");
word_store_integer(reg_epn, exception_get_epn());
break;
default:
word_store_string(reg_ema, "");
word_store_string(reg_epn, "");
}
if (mode == PRIVILEGE_USER)
{
machine_execute_interrupt_do(XSM_INTERRUPT_EXHANDLER);
return XSM_SUCCESS;
}
fprintf(stderr, "-----------------------------------\n");
if (_theoptions.debug)
{
fprintf(stderr, "%s: Entering Debug Mode.\n", message);
debug_show_interface();
}
else
fprintf(stderr, "%s.\n", message);
return XSM_FAILURE;
}
/* To be decided */
void machine_get_mem_access(int *mem_left, int *mem_right)
{
*mem_left = _thecpu.mem_left;
*mem_right = _thecpu.mem_right;
}
/* Actions before instruction execution */
void machine_pre_execute(int ip_val)
{
/* Debug if activated */
if (_theoptions.debug)
debug_next_step(ip_val);
/* Clear the potential watchpoint trigger */
_thecpu.mem_left = -1;
}
/* Actions after instruction execution */
void machine_post_execute()
{
int core;
xsm_word *dest_port;
core = machine_get_core();
if (_thecpu.timer[core] >= 0)
_thecpu.timer[core]--;
if (_thecpu.disk_wait > 0)
_thecpu.disk_wait--;
if (_thecpu.console_wait > 0)
_thecpu.console_wait--;
if (_thecpu.timer[core] == 0)
{
machine_execute_interrupt_do(XSM_INTERRUPT_TIMER);
_thecpu.timer[core] = _theoptions.timer;
}
else if (_thecpu.disk_state == XSM_DISK_BUSY)
{
if (_thecpu.disk_wait == 0 && machine_get_core() == PRIMARY_CORE)
{
if (_thecpu.disk_op.operation == XSM_DISKOP_LOAD)
{
machine_execute_load_do(_thecpu.disk_op.dest_page, _thecpu.disk_op.src_block);
machine_execute_interrupt_do(XSM_INTERRUPT_DISK);
}
else if (_thecpu.disk_op.operation == XSM_DISKOP_STORE)
{
machine_execute_store_do(_thecpu.disk_op.dest_page, _thecpu.disk_op.src_block);
machine_execute_interrupt_do(XSM_INTERRUPT_DISK);
}
_thecpu.disk_state = XSM_DISK_IDLE;
}
}
else if (_thecpu.console_state == XSM_CONSOLE_BUSY)
{
if (_thecpu.console_wait == 0 && machine_get_core() == PRIMARY_CORE)
{
if (_thecpu.console_op.operation == XSM_CONSOLE_PRINT)
{
machine_execute_print_do(&_thecpu.console_op.word);
machine_execute_interrupt_do(XSM_INTERRUPT_CONSOLE);
}
else if (_thecpu.console_op.operation == XSM_CONSOLE_READ)
{
machine_execute_in_do(&_thecpu.console_op.word);
dest_port = registers_get_register("P0", PRIMARY_CORE);
word_copy(dest_port, &_thecpu.console_op.word);
machine_execute_interrupt_do(XSM_INTERRUPT_CONSOLE);
}
_thecpu.console_state = XSM_CONSOLE_IDLE;
}
}
}
/* Call the function based on the given opcode */
int machine_execute_instruction(int opcode)
{
switch (opcode)
{
case MOV:
case PORT:
machine_execute_mov();
break;
case ADD:
case SUB:
case MUL:
case DIV:
case MOD:
machine_execute_arith(opcode);
break;
case INR:
case DCR:
machine_execute_unary(opcode);
break;
case LT:
case GT:
case EQ:
case NE:
case GE:
case LE:
machine_execute_logical(opcode);
break;
case JZ:
case JNZ:
case JMP:
machine_execute_jump(opcode);
break;
case PUSH:
case POP:
machine_execute_stack(opcode);
break;
case CALL:
machine_execute_call();
break;
case RET:
machine_execute_ret();
break;
case BRKP:
machine_execute_brkp();
break;
case INT:
machine_execute_interrupt();
break;
case LOAD:
machine_execute_disk(XSM_DISKOP_LOAD, FALSE);
break;
case LOADI:
machine_execute_disk(XSM_DISKOP_LOAD, TRUE);
break;
case STORE:
machine_execute_disk(XSM_DISKOP_STORE, FALSE);
break;
case ENCRYPT:
machine_execute_encrypt();
break;
case BACKUP:
machine_execute_backup();
break;
case RESTORE:
machine_execute_restore();
break;
case IN:
machine_schedule_in(_theoptions.console);
break;
case INI:
machine_execute_ini();
break;
case OUT:
machine_execute_print();
break;
case IRET:
machine_execute_iret();
break;
case TSL:
machine_execute_tsl();
break;
case START:
machine_execute_start();
break;
case RESET:
machine_execute_reset();
break;
case HALT:
return XSM_HALT;
case NOP:
// Do nothing
break;
}
return TRUE;
}
/* Returns the word stored in the instruction */
xsm_word *machine_get_address(int write)
{
int address = machine_get_address_int(write);
return machine_memory_get_word(address);
}
/* Returns the address in the instruction */
int machine_get_address_int(int write)
{
int token, address, ret_addr, core;
YYSTYPE token_info;
core = machine_get_core();
/* Skip the opening square bracket */
tokenize_next_token(&token_info);
token = tokenize_next_token(&token_info);
switch (token)
{
case TOKEN_REGISTER:
address = registers_get_integer(token_info.str, core);
break;
case TOKEN_NUMBER:
address = token_info.val;
break;
default:
machine_register_exception("Invalid memory derefence", EXP_ILLINSTR);
}
/* Neglect the closing bracket */
tokenize_next_token(&token_info);
ret_addr = machine_translate_address(address, write, OPER_FETCH, machine_get_core(), machine_get_mode());
return ret_addr;
}
/* Translate the logical address */
int machine_translate_address(int address, int write, int type, int core, int mode)
{
int ptbr, ptlr, ret_addr, curr_ip;
if (mode == PRIVILEGE_KERNEL)
return address;
ptbr = word_get_integer(registers_get_register("PTBR", core));
ptlr = word_get_integer(registers_get_register("PTLR", core));
ret_addr = memory_translate_address(ptbr, ptlr, address, write);
if (ret_addr < 0 && type == DEBUG_FETCH)
return ret_addr;
if (ret_addr < 0 && type == INSTR_FETCH)
{
curr_ip = word_get_integer(machine_get_ipreg());
curr_ip = curr_ip + XSM_INSTRUCTION_SIZE;
word_store_integer(machine_get_ipreg(), curr_ip);
}
if (XSM_MEM_NOWRITE == ret_addr)
{
exception_set_ma(address);
machine_register_exception("Access violation", EXP_ILLMEM);
}
else if (XSM_MEM_PAGEFAULT == ret_addr)
{
exception_set_epn(memory_addr_page(address));
machine_register_exception("Page fault", EXP_PAGEFAULT);
}
else if (XSM_MEM_ILLPAGE == ret_addr)
{
exception_set_ma(address);
machine_register_exception("Address outside logical address space", EXP_ILLMEM);
}
return ret_addr;
}
/* Retrieve the word in the given address from memory */
xsm_word *machine_memory_get_word(int address)
{
xsm_word *result = memory_get_word(address);
if (result == NULL)
{
exception_set_ma(address);
machine_register_exception("Illegal memory access", EXP_ILLMEM);
}
return result;
}
/* Execute MOV/PORT instructions */
int machine_execute_mov()
{
int token, mem_write_addr;
xsm_word *l_address, *r_address;
YYSTYPE token_info;
token = tokenize_peek(&token_info);
switch (token)
{
case TOKEN_DREF_L:
_thecpu.mem_left = machine_get_address_int(TRUE);
_thecpu.mem_right = _thecpu.mem_right;
l_address = machine_memory_get_word(_thecpu.mem_left);
break;
case TOKEN_REGISTER:
l_address = machine_get_register(token_info.str);
token = tokenize_next_token(&token_info);
break;
}
token = tokenize_next_token(&token_info);
if (token != TOKEN_COMMA)
machine_register_exception("Malformed instruction", EXP_ILLINSTR);
token = tokenize_peek(&token_info);
switch (token)
{
case TOKEN_DREF_L:
r_address = machine_get_address(FALSE);
word_copy(l_address, r_address);
break;
case TOKEN_REGISTER:
r_address = machine_read_register(token_info.str);
word_copy(l_address, r_address);
tokenize_next_token(&token_info);
break;
case TOKEN_NUMBER:
word_store_integer(l_address, token_info.val);
tokenize_next_token(&token_info);
break;
case TOKEN_STRING:
word_store_string(l_address, token_info.str);
tokenize_next_token(&token_info);
break;
}
return XSM_SUCCESS;
}
/* Execute arithmetic instructions */
int machine_execute_arith(int opcode)
{
int result, token, l_value, r_value;
xsm_reg *l_operand, *r_operand;
YYSTYPE token_info;
token = tokenize_next_token(&token_info);
if (token != TOKEN_REGISTER)
machine_register_exception("Wrong operand", EXP_ILLINSTR);
l_operand = machine_get_register(token_info.str);
l_value = word_get_integer(l_operand);
/* Neglect comma */
tokenize_next_token(&token_info);
token = tokenize_next_token(&token_info);
if (token == TOKEN_NUMBER)
r_value = token_info.val;
else
{
r_operand = machine_read_register(token_info.str);
r_value = word_get_integer(r_operand);
}
switch (opcode)
{
case ADD:
result = r_value + l_value;
break;
case SUB:
result = l_value - r_value;
break;
case MUL:
result = l_value * r_value;
break;
case DIV:
if (r_value == 0)
machine_register_exception("Integer division by zero", EXP_ARITH);
result = l_value / r_value;
break;
case MOD:
if (r_value == 0)
machine_register_exception("Integer modulo by zero", EXP_ARITH);
result = l_value % r_value;
break;
}
word_store_integer(l_operand, result);
return XSM_SUCCESS;
}
/* Execute unary instructions */
int machine_execute_unary(int opcode)
{
int token, val;
YYSTYPE token_info;
xsm_word *arg_reg;
token = tokenize_next_token(&token_info);
arg_reg = machine_get_register(token_info.str);
val = word_get_integer(arg_reg);
switch (opcode)
{
case INR:
val = val + 1;
break;
case DCR:
val = val - 1;
break;
}
word_store_integer(arg_reg, val);
return XSM_SUCCESS;
}
/* Execute logical instructions */
int machine_execute_logical(int opcode)
{
xsm_word *src_left_reg, *src_right_reg;
int token;
YYSTYPE token_info;
int result, val_left, val_right;
token = tokenize_next_token(&token_info);
src_left_reg = machine_get_register(token_info.str);
/* Comma */
token = tokenize_next_token(&token_info);
if (TOKEN_COMMA != token)
{
machine_register_exception("Incorrect logical instruction", EXP_ILLINSTR);
}
token = tokenize_next_token(&token_info);
src_right_reg = machine_read_register(token_info.str);
/* String operation */
if (word_get_unix_type(src_left_reg) == XSM_TYPE_STRING || word_get_unix_type(src_right_reg) == XSM_TYPE_STRING)
{
char *wor_left = word_get_string(src_left_reg);
char *wor_right = word_get_string(src_right_reg);
switch (opcode)
{
case LT:
result = strcmp(wor_left, wor_right) < 0 ? 1 : 0;
break;
case GT:
result = strcmp(wor_left, wor_right) > 0 ? 1 : 0;
break;
case EQ:
result = strcmp(wor_left, wor_right) == 0 ? 1 : 0;
break;
case NE:
result = strcmp(wor_left, wor_right) != 0 ? 1 : 0;
break;
case GE:
result = strcmp(wor_left, wor_right) >= 0 ? 1 : 0;
break;
case LE:
result = strcmp(wor_left, wor_right) <= 0 ? 1 : 0;
break;
}
}
else /* Integer operation */
{
val_left = word_get_integer(src_left_reg);
val_right = word_get_integer(src_right_reg);
switch (opcode)
{
case LT:
result = val_left < val_right ? 1 : 0;
break;
case GT:
result = val_left > val_right ? 1 : 0;
break;
case EQ:
result = val_left == val_right ? 1 : 0;
break;
case NE:
result = val_left != val_right ? 1 : 0;
break;
case GE:
result = val_left >= val_right ? 1 : 0;
break;
case LE:
result = val_left <= val_right ? 1 : 0;
break;
}
}
word_store_integer(src_left_reg, result);
return XSM_SUCCESS;
}
/* Execute jump instructions */
int machine_execute_jump(int opcode)
{
int test, target, token, core;
YYSTYPE token_info;
token = tokenize_next_token(&token_info);
core = machine_get_core();
if (token == TOKEN_NUMBER)
{
test = TRUE;
target = token_info.val;
}
else
{
// String content is true
if (word_get_unix_type(machine_read_register(token_info.str)) == XSM_TYPE_STRING)
test = 1;
else
test = word_get_integer(machine_read_register(token_info.str));
/* Skip the comma */
tokenize_next_token(&token_info);
token = tokenize_next_token(&token_info);
target = token_info.val;
}
if (JZ == opcode)
test = !test;
// Unconditional jump
if (test)
word_store_integer(registers_get_register("IP", core), target);
return XSM_SUCCESS;
}
/* Execute PUSH/POP instructions */
int machine_execute_stack(int opcode)
{
int token;
xsm_word *reg;
YYSTYPE token_info;
token = tokenize_next_token(&token_info);
if (token == TOKEN_REGISTER)
reg = machine_read_register(token_info.str);
else
machine_register_exception("Stack instructions require a register as argument", EXP_ILLINSTR);
switch (opcode)
{
case PUSH:
return machine_push_do(reg);
case POP:
return machine_pop_do(reg);
}
return XSM_SUCCESS;
}
/* Execute PUSH instruction */
int machine_push_do(xsm_word *reg)
{
int stack_top;
xsm_word *xw_stack_top, *sp_reg;
/* Update SP */
sp_reg = machine_get_spreg();
stack_top = word_get_integer(sp_reg);
word_store_integer(sp_reg, stack_top + 1);