static asm86_t *ack_get_statement(void)
/* Get a pseudo op or machine instruction with arguments. */
{
token_t *t= get_token(0);
asm86_t *a;
mnemonic_t *m;
int n;
int prefix_seen;
int oaz_prefix;
int deref;
assert(t->type == T_WORD);
if (strcmp(t->name, ".sect") == 0) {
/* .sect .text etc. Accept only four segment names. */
skip_token(1);
t= get_token(0);
if (t->type != T_WORD || (
strcmp(t->name, ".text") != 0
&& strcmp(t->name, ".rom") != 0
&& strcmp(t->name, ".data") != 0
&& strcmp(t->name, ".bss") != 0
&& strcmp(t->name, ".end") != 0
)) {
parse_err(1, t, "weird section name to .sect\n");
return nil;
}
}
a= new_asm86();
/* Process instruction prefixes. */
oaz_prefix= 0;
for (prefix_seen= 0;; prefix_seen= 1) {
if (strcmp(t->name, "o16") == 0) {
if (use16()) {
parse_err(1, t, "o16 in an 8086 section\n");
}
oaz_prefix|= OPZ;
} else
if (strcmp(t->name, "o32") == 0) {
if (use32()) {
parse_err(1, t, "o32 in an 80386 section\n");
}
oaz_prefix|= OPZ;
} else
if (strcmp(t->name, "a16") == 0) {
if (use16()) {
parse_err(1, t, "a16 in an 8086 section\n");
}
oaz_prefix|= ADZ;
} else
if (strcmp(t->name, "a32") == 0) {
if (use32()) {
parse_err(1, t, "a32 in an 80386 section\n");
}
oaz_prefix|= ADZ;
} else
if (strcmp(t->name, "rep") == 0
|| strcmp(t->name, "repe") == 0
|| strcmp(t->name, "repne") == 0
|| strcmp(t->name, "repz") == 0
|| strcmp(t->name, "repnz") == 0
) {
if (a->rep != ONCE) {
parse_err(1, t,
"can't have more than one rep\n");
}
switch (t->name[3]) {
case 0: a->rep= REP; break;
case 'e':
case 'z': a->rep= REPE; break;
case 'n': a->rep= REPNE; break;
}
} else
if (strchr("cdefgs", t->name[0]) != nil
&& strcmp(t->name+1, "seg") == 0) {
if (a->seg != DEFSEG) {
parse_err(1, t,
"can't have more than one segment prefix\n");
}
switch (t->name[0]) {
case 'c': a->seg= CSEG; break;
case 'd': a->seg= DSEG; break;
case 'e': a->seg= ESEG; break;
case 'f': a->seg= FSEG; break;
case 'g': a->seg= GSEG; break;
case 's': a->seg= SSEG; break;
}
} else
if (!prefix_seen) {
/* No prefix here, get out! */
break;
} else {
/* No more prefixes, next must be an instruction. */
if (t->type != T_WORD
|| (m= search_mnem(t->name)) == nil
|| m->optype == PSEUDO
) {
parse_err(1, t,
"machine instruction expected after instruction prefix\n");
del_asm86(a);
return nil;
}
if (oaz_prefix != 0 && m->optype != JUMP
&& m->optype != WORD) {
parse_err(1, t,
"'%s' can't have an operand size prefix\n", m->name);
}
break;
}
/* Skip the prefix and extra newlines. */
do {
skip_token(1);
} while ((t= get_token(0))->symbol == ';');
}
/* All the readahead being done upsets the line counter. */
a->line= t->line;
/* Read a machine instruction or pseudo op. */
if ((m= search_mnem(t->name)) == nil) {
parse_err(1, t, "unknown instruction '%s'\n", t->name);
del_asm86(a);
return nil;
}
a->opcode= m->opcode;
a->optype= m->optype;
a->oaz= oaz_prefix;
switch (a->opcode) {
case IN:
case OUT:
case INT:
deref= 0;
break;
default:
deref= (a->optype >= BYTE);
}
n= 1;
if (get_token(1)->symbol != ';'
&& (a->args= ack_get_oplist(&n, deref)) == nil) {
del_asm86(a);
return nil;
}
if (get_token(n)->symbol != ';') {
parse_err(1, t, "garbage at end of instruction\n");
del_asm86(a);
return nil;
}
switch (a->opcode) {
case DOT_ALIGN:
/* Restrict .align to have a single numeric argument, some
* assemblers think of the argument as a power of two, so
* we need to be able to change the value.
*/
if (a->args == nil || a->args->operator != 'W'
|| !isanumber(a->args->name)) {
parse_err(1, t,
".align is restricted to one numeric argument\n");
del_asm86(a);
return nil;
}
break;
case JMPF:
case CALLF:
/* NCC jmpf off,seg -> ACK jmpf seg:off */
if (dialect == NCC && a->args != nil
&& a->args->operator == ',') {
expression_t *t;
t= a->args->left;
a->args->left= a->args->right;
a->args->right= t;
break;
}
/*FALL THROUGH*/
case JMP:
case CALL:
/* NCC jmp @(reg) -> ACK jmp (reg) */
if (dialect == NCC && a->args != nil && (
(a->args->operator == '('
&& a->args->middle != nil
&& a->args->middle->operator == 'O')
|| (a->args->operator == 'O'
&& a->args->left == nil
&& a->args->middle != nil
&& a->args->right == nil)
)) {
expression_t *t;
t= a->args;
a->args= a->args->middle;
t->middle= nil;
del_expr(t);
if (a->args->operator == 'B') a->args->operator= 'W';
}
break;
default:;
}
skip_token(n+1);
return a;
}
static expression_t *ack_get_operand(asm86_t * a, int *pn, int deref)
/* Get something like: (memory), offset(base)(index*scale), or simpler. */
{
expression_t *e, *offset, *base, *index;
token_t *t;
int c;
/* Is it (memory)? */
if (get_token(*pn)->symbol == '('
&& ((t= get_token(*pn + 1))->type != T_WORD
|| !test_register(t->name, a))
) {
/* A memory dereference. */
(*pn)++;
if ((offset= ack_get_C_expression(pn, a)) == nil) return nil;
if (get_token(*pn)->symbol != ')') {
parse_err(1, t, "operand syntax error\n");
del_expr(offset);
return nil;
}
(*pn)++;
e= new_expr();
e->operator= '(';
e->middle= offset;
/*
* the default size is WORD however int on i386 is 32bit and the
* assembler cannot figure it out on its own. We are also taking
* our chance here though
*/
if (use32() && a->optype == WORD)
a->optype = OWORD;
return e;
}
/* #constant? */
if (dialect == NCC && deref
&& ((c= get_token(*pn)->symbol) == '#' || c == '*')) {
/* NCC: mov ax,#constant -> ACK: mov ax,constant */
(*pn)++;
return ack_get_C_expression(pn, a);
}
/* @address? */
if (dialect == NCC && get_token(*pn)->symbol == '@') {
/* NCC: jmp @address -> ACK: jmp (address) */
(*pn)++;
if ((offset= ack_get_operand(a, pn, deref)) == nil) return nil;
e= new_expr();
e->operator= '(';
e->middle= offset;
return e;
}
/* Offset? */
if (get_token(*pn)->symbol != '(') {
/* There is an offset. */
if ((offset= ack_get_C_expression(pn, a)) == nil) return nil;
} else {
/* No offset. */
offset= nil;
}
/* (base)? */
if (get_token(*pn)->symbol == '('
&& (t= get_token(*pn + 1))->type == T_WORD
&& test_register(t->name, a)
&& get_token(*pn + 2)->symbol == ')'
) {
/* A base register expression. */
base= new_expr();
base->operator= 'B';
base->name= copystr(t->name);
(*pn)+= 3;
} else {
/* No base register expression. */
base= nil;
}
/* (index*scale)? */
if (get_token(*pn)->symbol == '(') {
/* An index most likely. */
token_t *m= nil;
if (!( /* This must be true: */
(t= get_token(*pn + 1))->type == T_WORD
&& test_register(t->name, a)
&& (get_token(*pn + 2)->symbol == ')' || (
get_token(*pn + 2)->symbol == '*'
&& (m= get_token(*pn + 3))->type == T_WORD
&& strchr("1248", m->name[0]) != nil
&& m->name[1] == 0
&& get_token(*pn + 4)->symbol == ')'
))
)) {
/* Alas it isn't */
parse_err(1, t, "operand syntax error\n");
del_expr(offset);
del_expr(base);
return nil;
}
/* Found an index. */
index= new_expr();
index->operator= m == nil ? '1' : m->name[0];
index->name= copystr(t->name);
(*pn)+= (m == nil ? 3 : 5);
} else {
/* No index. */
index= nil;
}
if (dialect == NCC && deref && base == nil && index == nil
&& !(offset != nil && offset->operator == 'W'
&& test_register(offset->name, a))
) {
/* NCC: mov ax,thing -> ACK mov ax,(thing) */
e= new_expr();
e->operator= '(';
e->middle= offset;
return e;
}
if (base == nil && index == nil) {
/* Return a lone offset as is. */
e= offset;
} else {
e= new_expr();
e->operator= 'O';
e->left= offset;
e->middle= base;
e->right= index;
}
return e;
}
