/* Negate just a single ExprItem by building a -1*ei subexpression */
static void
expr_xform_neg_item(yasm_expr *e, yasm_expr__item *ei)
{
yasm_expr *sube = yasm_xmalloc(sizeof(yasm_expr));
/* Build -1*ei subexpression */
sube->op = YASM_EXPR_MUL;
sube->line = e->line;
sube->numterms = 2;
sube->terms[0].type = YASM_EXPR_INT;
sube->terms[0].data.intn = yasm_intnum_create_int(-1);
sube->terms[1] = *ei; /* structure copy */
/* Replace original ExprItem with subexp */
ei->type = YASM_EXPR_EXPR;
ei->data.expn = sube;
}
static int
lc3b_bc_insn_tobytes(yasm_bytecode *bc, unsigned char **bufp,
unsigned char *bufstart, void *d,
yasm_output_value_func output_value,
/*@unused@*/ yasm_output_reloc_func output_reloc)
{
lc3b_insn *insn = (lc3b_insn *)bc->contents;
/*@only@*/ yasm_intnum *delta;
unsigned long buf_off = (unsigned long)(*bufp - bufstart);
/* Output opcode */
YASM_SAVE_16_L(*bufp, insn->opcode);
/* Insert immediate into opcode. */
switch (insn->imm_type) {
case LC3B_IMM_NONE:
break;
case LC3B_IMM_4:
insn->imm.size = 4;
if (output_value(&insn->imm, *bufp, 2, buf_off, bc, 1, d))
return 1;
break;
case LC3B_IMM_5:
insn->imm.size = 5;
insn->imm.sign = 1;
if (output_value(&insn->imm, *bufp, 2, buf_off, bc, 1, d))
return 1;
break;
case LC3B_IMM_6_WORD:
insn->imm.size = 6;
if (output_value(&insn->imm, *bufp, 2, buf_off, bc, 1, d))
return 1;
break;
case LC3B_IMM_6_BYTE:
insn->imm.size = 6;
insn->imm.sign = 1;
if (output_value(&insn->imm, *bufp, 2, buf_off, bc, 1, d))
return 1;
break;
case LC3B_IMM_8:
insn->imm.size = 8;
if (output_value(&insn->imm, *bufp, 2, buf_off, bc, 1, d))
return 1;
break;
case LC3B_IMM_9_PC:
/* Adjust relative displacement to end of bytecode */
delta = yasm_intnum_create_int(-1);
if (!insn->imm.abs)
insn->imm.abs = yasm_expr_create_ident(yasm_expr_int(delta),
bc->line);
else
insn->imm.abs =
yasm_expr_create(YASM_EXPR_ADD,
yasm_expr_expr(insn->imm.abs),
yasm_expr_int(delta), bc->line);
insn->imm.size = 9;
insn->imm.sign = 1;
if (output_value(&insn->imm, *bufp, 2, buf_off, bc, 1, d))
return 1;
break;
case LC3B_IMM_9:
insn->imm.size = 9;
if (output_value(&insn->imm, *bufp, 2, buf_off, bc, 1, d))
return 1;
break;
default:
yasm_internal_error(N_("Unrecognized immediate type"));
}
*bufp += 2; /* all instructions are 2 bytes in size */
return 0;
}
/* Negates e by multiplying by -1, with distribution over lower-precedence
* operators (eg ADD) and special handling to simplify result w/ADD, NEG, and
* others.
*
* Returns a possibly reallocated e.
*/
static /*@only@*/ yasm_expr *
expr_xform_neg_helper(/*@returned@*/ /*@only@*/ yasm_expr *e)
{
yasm_expr *ne;
int i;
switch (e->op) {
case YASM_EXPR_ADD:
/* distribute (recursively if expr) over terms */
for (i=0; i<e->numterms; i++) {
if (e->terms[i].type == YASM_EXPR_EXPR)
e->terms[i].data.expn =
expr_xform_neg_helper(e->terms[i].data.expn);
else
expr_xform_neg_item(e, &e->terms[i]);
}
break;
case YASM_EXPR_SUB:
/* change op to ADD, and recursively negate left side (if expr) */
e->op = YASM_EXPR_ADD;
if (e->terms[0].type == YASM_EXPR_EXPR)
e->terms[0].data.expn =
expr_xform_neg_helper(e->terms[0].data.expn);
else
expr_xform_neg_item(e, &e->terms[0]);
break;
case YASM_EXPR_NEG:
/* Negating a negated value? Make it an IDENT. */
e->op = YASM_EXPR_IDENT;
break;
case YASM_EXPR_IDENT:
/* Negating an ident? Change it into a MUL w/ -1 if there's no
* floatnums present below; if there ARE floatnums, recurse.
*/
if (e->terms[0].type == YASM_EXPR_FLOAT)
yasm_floatnum_calc(e->terms[0].data.flt, YASM_EXPR_NEG, NULL);
else if (e->terms[0].type == YASM_EXPR_INT)
yasm_intnum_calc(e->terms[0].data.intn, YASM_EXPR_NEG, NULL);
else if (e->terms[0].type == YASM_EXPR_EXPR &&
yasm_expr__contains(e->terms[0].data.expn, YASM_EXPR_FLOAT))
expr_xform_neg_helper(e->terms[0].data.expn);
else {
e->op = YASM_EXPR_MUL;
e->numterms = 2;
e->terms[1].type = YASM_EXPR_INT;
e->terms[1].data.intn = yasm_intnum_create_int(-1);
}
break;
default:
/* Everything else. MUL will be combined when it's leveled.
* Make a new expr (to replace e) with -1*e.
*/
ne = yasm_xmalloc(sizeof(yasm_expr));
ne->op = YASM_EXPR_MUL;
ne->line = e->line;
ne->numterms = 2;
ne->terms[0].type = YASM_EXPR_INT;
ne->terms[0].data.intn = yasm_intnum_create_int(-1);
ne->terms[1].type = YASM_EXPR_EXPR;
ne->terms[1].data.expn = e;
return ne;
}
return e;
}
