"tosltax", "tosultax", "toslteax", "tosulteax",
};
+ unsigned Label;
+
/* If the right hand side is const, the lhs is not on stack but still
* in the primary register.
*/
} else if (val == 0) {
- /* Look at the type */
+ /* A signed compare against zero must only look at the sign bit */
switch (flags & CF_TYPE) {
case CF_CHAR:
if (flags & CF_FORCECHAR) {
- AddCodeLine ("tax");
- AddCodeLine ("jsr boollt");
+ AddCodeLine ("asl a"); /* Bit 7 -> carry */
+ AddCodeLine ("ldx #$00");
+ AddCodeLine ("lda #$00");
+ AddCodeLine ("rol a");
return;
}
/* FALLTHROUGH */
case CF_INT:
/* Just check the high byte */
- AddCodeLine ("txa");
- AddCodeLine ("jsr boollt");
+ AddCodeLine ("cpx #$80"); /* Bit 7 -> carry */
+ AddCodeLine ("ldx #$00");
+ AddCodeLine ("lda #$00");
+ AddCodeLine ("rol a");
return;
case CF_LONG:
/* Just check the high byte */
AddCodeLine ("lda sreg+1");
- AddCodeLine ("jsr boollt");
+ AddCodeLine ("asl a"); /* Bit 7 -> carry */
+ AddCodeLine ("ldx #$00");
+ AddCodeLine ("lda #$00");
+ AddCodeLine ("rol a");
+ return;
+
+ default:
+ typeerror (flags);
+ }
+
+ } else {
+
+ /* Signed compare against a constant != zero */
+ switch (flags & CF_TYPE) {
+
+ case CF_CHAR:
+ if (flags & CF_FORCECHAR) {
+ Label = GetLocalLabel ();
+ AddCodeLine ("sec");
+ AddCodeLine ("sbc #$%02X", (unsigned char)val);
+ AddCodeLine ("bvc %s", LocalLabelName (Label));
+ AddCodeLine ("eor #$80");
+ g_defcodelabel (Label);
+ AddCodeLine ("asl a"); /* Bit 7 -> carry */
+ AddCodeLine ("ldx #$00");
+ AddCodeLine ("lda #$00");
+ AddCodeLine ("rol a");
+ return;
+ }
+ /* FALLTHROUGH */
+
+ case CF_INT:
+ /* Do a subtraction */
+ Label = GetLocalLabel ();
+ AddCodeLine ("cmp #$%02X", (unsigned char)val);
+ AddCodeLine ("txa");
+ AddCodeLine ("sbc #$%02X", (unsigned char)(val >> 8));
+ AddCodeLine ("bvc %s", LocalLabelName (Label));
+ AddCodeLine ("eor #$80");
+ g_defcodelabel (Label);
+ AddCodeLine ("asl a"); /* Bit 7 -> carry */
+ AddCodeLine ("ldx #$00");
+ AddCodeLine ("lda #$00");
+ AddCodeLine ("rol a");
return;
+ case CF_LONG:
+ /* This one is too costly */
+ break;
+
default:
typeerror (flags);
}
+
}
/* If we go here, we didn't emit code. Push the lhs on stack and fall
case CF_CHAR:
if (flags & CF_FORCECHAR) {
+ /* Do a subtraction. Condition is true if carry set */
AddCodeLine ("cmp #$%02X", (unsigned char)val);
- AddCodeLine ("jsr booluge");
+ AddCodeLine ("lda #$00");
+ AddCodeLine ("ldx #$00");
+ AddCodeLine ("rol a");
return;
}
/* FALLTHROUGH */
case CF_INT:
- /* If the low byte is zero, we must only test the high byte */
- AddCodeLine ("cpx #$%02X", (unsigned char)(val >> 8));
- if ((val & 0xFF) != 0) {
- unsigned L = GetLocalLabel();
- AddCodeLine ("bne %s", LocalLabelName (L));
- AddCodeLine ("cmp #$%02X", (unsigned char)val);
- g_defcodelabel (L);
- }
- AddCodeLine ("jsr booluge");
+ /* Do a subtraction. Condition is true if carry set */
+ AddCodeLine ("cmp #$%02X", (unsigned char)val);
+ AddCodeLine ("txa");
+ AddCodeLine ("sbc #$%02X", (unsigned char)(val >> 8));
+ AddCodeLine ("lda #$00");
+ AddCodeLine ("ldx #$00");
+ AddCodeLine ("rol a");
return;
case CF_LONG:
- /* Do a subtraction */
+ /* Do a subtraction. Condition is true if carry set */
AddCodeLine ("cmp #$%02X", (unsigned char)val);
AddCodeLine ("txa");
AddCodeLine ("sbc #$%02X", (unsigned char)(val >> 8));
AddCodeLine ("sbc #$%02X", (unsigned char)(val >> 16));
AddCodeLine ("lda sreg+1");
AddCodeLine ("sbc #$%02X", (unsigned char)(val >> 24));
- AddCodeLine ("jsr booluge");
+ AddCodeLine ("lda #$00");
+ AddCodeLine ("ldx #$00");
+ AddCodeLine ("rol a");
return;
default:
} else if (val == 0) {
- /* Look at the type */
+ /* A signed compare against zero must only look at the sign bit */
switch (flags & CF_TYPE) {
case CF_CHAR:
* ldx tmp1
*
* which makes 4 + 3 * ShiftCount bytes, compared to the original
- * 3 bytes for the subroutine call. However, in most cases, the
+ * 3 bytes for the subroutine call. However, in most cases, the
* final load of the X register gets merged with some other insn
* and replaces a txa, so for a shift count of 1, we get a factor
* of 200, which matches nicely the CodeSizeFactor enabled with -Oi
- */
+ */
if (ShiftCount > 1 || S->CodeSizeFactor > 200) {
unsigned Size = 4 + 3 * ShiftCount;
if ((Size * 100 / 3) > S->CodeSizeFactor) {
static OptFunc DOptCmp6 = { OptCmp6, "OptCmp6", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptCmp7 = { OptCmp7, "OptCmp7", 85, 0, 0, 0, 0, 0 };
static OptFunc DOptCmp8 = { OptCmp8, "OptCmp8", 50, 0, 0, 0, 0, 0 };
-static OptFunc DOptCondBranches = { OptCondBranches, "OptCondBranches", 80, 0, 0, 0, 0, 0 };
+static OptFunc DOptCondBranches1= { OptCondBranches1,"OptCondBranches1", 80, 0, 0, 0, 0, 0 };
+static OptFunc DOptCondBranches2= { OptCondBranches2,"OptCondBranches2", 0, 0, 0, 0, 0, 0 };
static OptFunc DOptDeadCode = { OptDeadCode, "OptDeadCode", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptDeadJumps = { OptDeadJumps, "OptDeadJumps", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptDecouple = { OptDecouple, "OptDecouple", 100, 0, 0, 0, 0, 0 };
&DOptCmp6,
&DOptCmp7,
&DOptCmp8,
- &DOptCondBranches,
+ &DOptCondBranches1,
+ &DOptCondBranches2,
&DOptDeadCode,
&DOptDeadJumps,
&DOptDecouple,
C += RunOptFunc (S, &DOptDeadCode, 1);
C += RunOptFunc (S, &DOptJumpTarget1, 1);
C += RunOptFunc (S, &DOptJumpTarget2, 1);
- C += RunOptFunc (S, &DOptCondBranches, 1);
+ C += RunOptFunc (S, &DOptCondBranches1, 1);
+ C += RunOptFunc (S, &DOptCondBranches2, 1);
C += RunOptFunc (S, &DOptRTSJumps1, 1);
C += RunOptFunc (S, &DOptBoolTrans, 1);
C += RunOptFunc (S, &DOptCmp1, 1);
-unsigned OptCondBranches (CodeSeg* S)
+unsigned OptCondBranches1 (CodeSeg* S)
/* Performs several optimization steps:
*
* - If an immidiate load of a register is followed by a conditional jump that
+unsigned OptCondBranches2 (CodeSeg* S)
+/* If on entry to a "rol a" instruction the accu is zero, and a beq/bne follows,
+ * we can remove the rol and branch on the state of the carry.
+ */
+{
+ unsigned Changes = 0;
+
+ /* Generate register info for this step */
+ CS_GenRegInfo (S);
+
+ /* Walk over the entries */
+ unsigned I = 0;
+ while (I < CS_GetEntryCount (S)) {
+
+ CodeEntry* N;
+
+ /* Get next entry */
+ CodeEntry* E = CS_GetEntry (S, I);
+
+ /* Check if it's a rol insn with A in accu and a branch follows */
+ if (E->OPC == OP65_ROL &&
+ E->AM == AM65_ACC &&
+ E->RI->In.RegA == 0 &&
+ !CE_HasLabel (E) &&
+ (N = CS_GetNextEntry (S, I)) != 0 &&
+ (N->Info & OF_ZBRA) != 0 &&
+ !RegAUsed (S, I+1)) {
+
+ /* Replace the branch condition */
+ switch (GetBranchCond (N->OPC)) {
+ case BC_EQ: CE_ReplaceOPC (N, OP65_JCC); break;
+ case BC_NE: CE_ReplaceOPC (N, OP65_JCS); break;
+ default: Internal ("Unknown branch condition in OptCondBranches2");
+ }
+
+ /* Delete the rol insn */
+ CS_DelEntry (S, I);
+
+ /* Remember, we had changes */
+ ++Changes;
+
+ }
+
+ /* Next entry */
+ ++I;
+
+ }
+
+ /* Free register info */
+ CS_FreeRegInfo (S);
+
+ /* Return the number of changes made */
+ return Changes;
+}
+
+
+
/*****************************************************************************/
/* Remove unused loads and stores */
/*****************************************************************************/
* remove the store.
*/
if (RegValIsKnown (In->RegA) && /* Value of A is known */
- E->AM == AM65_ZP && /* Store into zp */
+ E->AM == AM65_ZP && /* Store into zp */
In->RegA == ZPRegVal (E->Chg, In)) { /* Value identical */
Delete = 1;
*/
} else if (RegValIsKnown (In->RegY)) {
if (In->RegY == In->RegA) {
- CE_ReplaceOPC (E, OP65_STA);
+ CE_ReplaceOPC (E, OP65_STA);
} else if (In->RegY == In->RegX &&
E->AM != AM65_ABSX &&
E->AM != AM65_ZPX) {
case OP65_TYA:
if (RegValIsKnown (In->RegY) &&
- In->RegY == In->RegA &&
+ In->RegY == In->RegA &&
(N = CS_GetNextEntry (S, I)) != 0 &&
!CE_UseLoadFlags (N)) {
/* Value is identical and not followed by a branch */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
- CodeEntry* N;
- CodeEntry* X;
+ CodeEntry* N;
+ CodeEntry* X;
- /* Get next entry */
+ /* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check if it is a store instruction followed by a load from the
/*****************************************************************************/
-
+
unsigned OptBranchDist (CodeSeg* S)
/* Change branches for the distance needed. */
{
* it's job is already done.
*/
-unsigned OptCondBranches (CodeSeg* S);
+unsigned OptCondBranches1 (CodeSeg* S);
/* If an immidiate load of a register is followed by a conditional jump that
* is never taken because the load of the register sets the flags in such a
* manner, remove the conditional branch.
*/
+unsigned OptCondBranches2 (CodeSeg* S);
+/* If on entry to a "rol a" instruction the accu is zero, and a beq/bne follows,
+ * we can remove the rol and branch on the state of the carry.
+ */
+
unsigned OptUnusedLoads (CodeSeg* S);
/* Remove loads of registers where the value loaded is not used later. */
projects / cc65 / commitdiff