Address expressions are now fully algebraic.

This commit is contained in:
Daniel Beer 2010-04-10 12:25:01 +12:00
parent f8f530f24e
commit aecf8f0175
2 changed files with 256 additions and 64 deletions

View File

@ -296,17 +296,21 @@ renamed.
.SH ADDRESS EXPRESSIONS
Any command which accepts a memory address, length or register value
as an argument may be given an address expression. An address
expression consists of a sequence of one or more address values
separated by the operators \fB+\fR or \fB\-\fR.
expression consists of an algebraic combination of values.
An address value may be either a decimal value, a hexadecimal value
preceeded by the prefix \fB0x\fR, or a symbol name.
The operators recognised are the usual algebraic operators: \fB+\fR, \fB-\fR,
\fB*\fR, \fB/\fR, \fB%\fR, \fB(\fR and \fB)\fR. Operator precedence is the
same as in C-like languages, and the \fB-\fR operator may be used as a
unary negation operator.
The following are all valid examples of address expressions:
.B 64
.B 2+2
.br
.B 0xffe0
.B table_start + (elem_size + elem_pad)*4
.br
.B main+0x3f
.br

308
util.c
View File

@ -27,6 +27,7 @@
#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <assert.h>
#ifdef USE_READLINE
#include <readline/readline.h>
@ -665,82 +666,269 @@ int ctrlc_check(void)
return ctrlc_flag;
}
static char token_buf[64];
static int token_len;
static int token_mult;
static int token_sum;
static token_func_t token_func;
static int token_add(void)
{
int i;
int value;
if (!token_len)
return 0;
token_buf[token_len] = 0;
token_len = 0;
/* Is it a decimal? */
i = 0;
while (token_buf[i] && isdigit(token_buf[i]))
i++;
if (!token_buf[i]) {
token_sum += token_mult * atoi(token_buf);
return 0;
}
/* Is it hex? */
if (token_buf[0] == '0' && tolower(token_buf[1]) == 'x') {
token_sum += token_mult * strtol(token_buf + 2, NULL, 16);
return 0;
}
/* Look up the name in the symbol table */
if (token_func && !token_func(token_buf, &value)) {
token_sum += token_mult * value;
return 0;
}
fprintf(stderr, "unknown token: %s\n", token_buf);
return -1;
}
void set_token_func(token_func_t func)
{
token_func = func;
}
int addr_exp(const char *text, int *addr)
{
token_len = 0;
token_mult = 1;
token_sum = 0;
struct addr_exp_state {
int last_operator;
int data_stack[32];
int data_stack_size;
int op_stack[32];
int op_stack_size;
};
while (*text) {
if (isalnum(*text) || *text == '_' || *text == '$' ||
*text == '.' || *text == ':') {
if (token_len + 1 < sizeof(token_buf))
token_buf[token_len++] = *text;
} else {
if (token_add() < 0)
static int addr_exp_data(struct addr_exp_state *s, const char *text)
{
int value;
if (!s->last_operator || s->last_operator == ')') {
fprintf(stderr, "syntax error at token %s\n", text);
return -1;
}
/* Hex value */
if (*text == '0' && text[1] == 'x')
value = strtoul(text + 2, NULL, 16);
else if (isdigit(*text))
value = atoi(text);
else if (!token_func || token_func(text, &value) < 0) {
fprintf(stderr, "can't parse token: %s\n", text);
return -1;
}
if (s->data_stack_size + 1 > ARRAY_LEN(s->data_stack)) {
fprintf(stderr, "data stack overflow at token %s\n", text);
return -1;
}
s->data_stack[s->data_stack_size++] = value;
s->last_operator = 0;
return 0;
}
static int addr_exp_pop(struct addr_exp_state *s)
{
char op = s->op_stack[--s->op_stack_size];
int data1 = s->data_stack[--s->data_stack_size];
int data2 = 0;
int result = 0;
if (op != 'N')
data2 = s->data_stack[--s->data_stack_size];
assert (s->op_stack_size >= 0);
assert (s->data_stack_size >= 0);
switch (op) {
case '+':
result = data2 + data1;
break;
case '-':
result = data2 - data1;
break;
case '*':
result = data2 * data1;
break;
case '/':
if (!data1)
goto divzero;
result = data2 / data1;
break;
case '%':
if (!data1)
goto divzero;
result = data2 % data1;
break;
case 'N':
result = -data1;
break;
}
s->data_stack[s->data_stack_size++] = result;
return 0;
divzero:
fprintf(stderr, "divide by zero\n");
return -1;
}
static int can_push(struct addr_exp_state *s, char op)
{
char top;
if (!s->op_stack_size || op == '(')
return 1;
top = s->op_stack[s->op_stack_size - 1];
if (top == '(')
return 1;
switch (op) {
case 'N':
return 1;
case '*':
case '%':
case '/':
return top == '+' || top == '-';
default:
break;
}
return 0;
}
static int addr_exp_op(struct addr_exp_state *s, char op)
{
if (op == '(') {
if (!s->last_operator || s->last_operator == ')')
goto syntax_error;
} else if (op == '-') {
if (s->last_operator && s->last_operator != ')')
op = 'N';
} else {
if (s->last_operator && s->last_operator != ')')
goto syntax_error;
}
if (op == ')') {
/* ) collapses the stack to the last matching ( */
while (s->op_stack_size &&
s->op_stack[s->op_stack_size - 1] != '(')
if (addr_exp_pop(s) < 0)
return -1;
if (*text == '+')
token_mult = 1;
if (*text == '-')
token_mult = -1;
if (!s->op_stack_size) {
fprintf(stderr, "parenthesis mismatch: )\n");
return -1;
}
s->op_stack_size--;
} else {
while (!can_push(s, op))
if (addr_exp_pop(s) < 0)
return -1;
if (s->op_stack_size + 1 > ARRAY_LEN(s->op_stack)) {
fprintf(stderr, "operator stack overflow: %c\n", op);
return -1;
}
s->op_stack[s->op_stack_size++] = op;
}
s->last_operator = op;
return 0;
syntax_error:
fprintf(stderr, "syntax error at operator %c\n", op);
return -1;
}
static int addr_exp_finish(struct addr_exp_state *s, int *ret)
{
if (s->last_operator && s->last_operator != ')') {
fprintf(stderr, "syntax error at end of expression\n");
return -1;
}
while (s->op_stack_size) {
if (s->op_stack[s->op_stack_size - 1] == '(') {
fprintf(stderr, "parenthesis mismatch: (\n");
return -1;
}
if (addr_exp_pop(s) < 0)
return -1;
}
if (s->data_stack_size != 1) {
fprintf(stderr, "no data: stack size is %d\n",
s->data_stack_size);
return -1;
}
if (ret)
*ret = s->data_stack[0];
return 0;
}
int addr_exp(const char *text, int *addr)
{
const char *text_save = text;
int last_cc = 1;
char token_buf[64];
int token_len = 0;
struct addr_exp_state s = {0};
s.last_operator = '(';
for (;;) {
int cc;
/* Figure out what class this character is */
if (*text == '+' || *text == '-' ||
*text == '*' || *text == '/' ||
*text == '%' || *text == '(' ||
*text == ')')
cc = 1;
else if (!*text || isspace(*text))
cc = 2;
else if (isalnum(*text) || *text == '.' || *text == '_' ||
*text == '$' || *text == ':')
cc = 3;
else {
fprintf(stderr, "illegal character in expression: %c\n",
*text);
return -1;
}
/* Accumulate and process token text */
if (cc == 3) {
if (token_len + 1 < sizeof(token_buf))
token_buf[token_len++] = *text;
} else if (token_len) {
token_buf[token_len] = 0;
token_len = 0;
if (addr_exp_data(&s, token_buf) < 0)
goto fail;
}
/* Process operators */
if (cc == 1) {
if (addr_exp_op(&s, *text) < 0)
goto fail;
}
if (!*text)
break;
last_cc = cc;
text++;
}
if (token_add() < 0)
return -1;
if (addr_exp_finish(&s, addr) < 0)
goto fail;
*addr = token_sum & 0xffff;
return 0;
fail:
fprintf(stderr, "bad address expression: %s\n", text_save);
return -1;
}
static int modify_flags;