/* These insns are all ok and replaceable */
D->Flags |= OP_DIRECT;
} else if (E->AM == AM65_ZP_INDY && RegValIsKnown (E->RI->In.RegY) &&
- strcmp (E->Arg, D->ZPLo) != 0 && strcmp (E->Arg, D->ZPHi) != 0) {
- /* Load indirect with known offset is also ok, provided that
- * the zeropage location used is not the same as the one we're
- * using for the temp storage.
+ strcmp (E->Arg, "sp") == 0) {
+ /* A load from the stack with known offset is also ok, but in this
+ * case we must reload the index register later. Please note that
+ * a load indirect via other zero page locations is not ok, since
+ * these locations may change between the push and the actual
+ * operation.
*/
D->Flags |= (OP_DIRECT | OP_RELOAD_Y);
}
/* Handling depends if we're inside a sequence or not */
if (InSeq) {
- if (((E->Use & REG_SP) != 0 &&
- (E->AM != AM65_ZP_INDY || RegValIsUnknown (E->RI->In.RegY)))) {
+ /* If we are using the stack, and we don't have "indirect Y"
+ * addressing mode, or the value of Y is unknown, or less than
+ * two, we cannot cope with this piece of code. Having an unknown
+ * value of Y means that we cannot correct the stack offset, while
+ * having an offset less than two means that the code works with
+ * the value on stack which is to be removed.
+ */
+ if ((E->Use & REG_SP) != 0 &&
+ (E->AM != AM65_ZP_INDY || RegValIsUnknown (E->RI->In.RegY) ||
+ E->RI->In.RegY < 2)) {
/* All this stuff is not allowed in a sequence */
InSeq = 0;