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Name the addressing modes.

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This commit is contained in:
Olaf Seibert 2021-06-12 18:37:45 +02:00
parent 7f38f6ae03
commit 0058db9044
2 changed files with 23 additions and 13 deletions
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7
assemble_aux.h
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@ -19,6 +19,13 @@ typedef struct addr_mode {
EX_TREE *offset; /* Expression giving the offset */
} ADDR_MODE;
#define MODE_INDIRECT 010 /* (R0), @(R0)+, @-(R0), @42(R0) */
#define MODE_REG 000 /* R0 */
#define MODE_AUTO_INCR 020 /* (R0)+ */
#define MODE_AUTO_DECR 040 /* -(R0) */
#define MODE_OFFSET 060 /* 42(R0) */
#define MODE_PC 007
void push_cond(
int ok,
STREAM *str);

29
parse.c
View File

@ -202,13 +202,14 @@ int get_mode(
/* @ means "indirect," sets bit 3 */
if (*cp == '@') {
cp++;
mode->type |= 010;
mode->type |= MODE_INDIRECT;
}
/* Immediate modes #imm and @#imm */
if (*cp == '#') {
cp++;
mode->type |= 027;
mode->type |= MODE_AUTO_INCR | MODE_PC;
mode->offset = parse_expr(cp, 0);
if (endp)
*endp = mode->offset->cp;
@ -240,7 +241,7 @@ int get_mode(
free_tree(value);
return FALSE;
}
mode->type |= 040 | reg;
mode->type |= MODE_AUTO_DECR | reg;
if (endp)
*endp = tcp;
free_tree(value);
@ -272,22 +273,23 @@ int get_mode(
tcp++; /* It's (Rn)+ */
if (endp)
*endp = tcp;
mode->type |= 020 | reg;
mode->type |= MODE_AUTO_INCR | reg;
free_tree(value);
return TRUE;
}
if (mode->type == 010) { /* For @(Rn) there's an implied 0 offset */
if (mode->type == MODE_INDIRECT) { /* For @(Rn) there's an
implied 0 offset */
mode->offset = new_ex_lit(0);
mode->type |= 060 | reg;
mode->type |= MODE_OFFSET | reg;
free_tree(value);
if (endp)
*endp = tcp;
return TRUE;
}
mode->type |= 010 | reg; /* Mode 10 is register indirect as
in (Rn) */
mode->type |= MODE_INDIRECT | reg; /* Mode 10 is register indirect
as in (Rn) */
free_tree(value);
if (endp)
*endp = tcp;
@ -322,7 +324,7 @@ int get_mode(
return FALSE; /* Syntax error in addressing mode */
}
mode->type |= 060 | reg;
mode->type |= MODE_OFFSET | reg;
free_tree(value);
@ -351,14 +353,15 @@ int get_mode(
/* It's either 067 (PC-relative) or 037 (absolute) mode, depending */
/* on user option. */
if (mode->type & 010) { /* Have already noted indirection? */
mode->type |= 067; /* If so, then PC-relative is the only
if (mode->type & MODE_INDIRECT) { /* Have already noted indirection? */
mode->type |= MODE_OFFSET|MODE_PC;/* If so, then PC-relative is the only
option */
mode->rel = 1; /* Note PC-relative */
} else if (enabl_ama) { /* User asked for absolute adressing? */
mode->type |= 037; /* Give it to him. */
mode->type |= MODE_INDIRECT|MODE_AUTO_INCR|MODE_PC;
/* Give it to him. */
} else {
mode->type |= 067; /* PC-relative */
mode->type |= MODE_OFFSET|MODE_PC; /* PC-relative */
mode->rel = 1; /* Note PC-relative */
}