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Better code for compares

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git-svn-id: svn://svn.cc65.org/cc65/trunk@1150 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
cuz
2002-02-12 20:40:05 +00:00
parent 0de448df64
commit 08443d5e7a
1 changed files with 120 additions and 62 deletions
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182
src/cc65/codegen.c
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@@ -1748,7 +1748,7 @@ void g_subeqstatic (unsigned flags, unsigned long label, long offs,
AddCodeLine ("sbc #$%02X", (int)(val & 0xFF)); AddCodeLine ("sbc #$%02X", (int)(val & 0xFF));
AddCodeLine ("sta %s", lbuf); AddCodeLine ("sta %s", lbuf);
} }
} else { } else {
AddCodeLine ("eor #$FF"); AddCodeLine ("eor #$FF");
AddCodeLine ("sec"); AddCodeLine ("sec");
AddCodeLine ("adc %s", lbuf); AddCodeLine ("adc %s", lbuf);
@@ -1783,7 +1783,7 @@ void g_subeqstatic (unsigned flags, unsigned long label, long offs,
AddCodeLine ("tax"); AddCodeLine ("tax");
AddCodeLine ("lda %s", lbuf); AddCodeLine ("lda %s", lbuf);
} }
} else { } else {
AddCodeLine ("eor #$FF"); AddCodeLine ("eor #$FF");
AddCodeLine ("adc %s", lbuf); AddCodeLine ("adc %s", lbuf);
AddCodeLine ("sta %s", lbuf); AddCodeLine ("sta %s", lbuf);
@@ -3219,9 +3219,9 @@ void g_eq (unsigned flags, unsigned long val)
{ {
static char* ops [12] = { static char* ops [12] = {
"toseq00", "toseqa0", "toseqax", "toseq00", "toseqa0", "toseqax",
"toseq00", "toseqa0", "toseqax", "toseq00", "toseqa0", "toseqax",
0, 0, "toseqeax", 0, 0, "toseqeax",
0, 0, "toseqeax", 0, 0, "toseqeax",
}; };
unsigned L; unsigned L;
@@ -3332,7 +3332,7 @@ void g_lt (unsigned flags, unsigned long val)
static char* ops [12] = { static char* ops [12] = {
"toslt00", "toslta0", "tosltax", "toslt00", "toslta0", "tosltax",
"tosult00", "tosulta0", "tosultax", "tosult00", "tosulta0", "tosultax",
0, 0, "toslteax", 0, 0, "toslteax",
0, 0, "tosulteax", 0, 0, "tosulteax",
}; };
@@ -3344,6 +3344,8 @@ void g_lt (unsigned flags, unsigned long val)
/* Give a warning in some special cases */ /* Give a warning in some special cases */
if ((flags & CF_UNSIGNED) && val == 0) { if ((flags & CF_UNSIGNED) && val == 0) {
Warning ("Condition is never true"); Warning ("Condition is never true");
AddCodeLine ("jsr return0");
return;
} }
/* Look at the type */ /* Look at the type */
@@ -3353,7 +3355,7 @@ void g_lt (unsigned flags, unsigned long val)
if (flags & CF_FORCECHAR) { if (flags & CF_FORCECHAR) {
AddCodeLine ("cmp #$%02X", (unsigned char)val); AddCodeLine ("cmp #$%02X", (unsigned char)val);
if (flags & CF_UNSIGNED) { if (flags & CF_UNSIGNED) {
AddCodeLine ("jsr boolult"); AddCodeLine ("jsr boolult");
} else { } else {
AddCodeLine ("jsr boollt"); AddCodeLine ("jsr boollt");
} }
@@ -3370,16 +3372,32 @@ void g_lt (unsigned flags, unsigned long val)
AddCodeLine ("jsr boollt"); AddCodeLine ("jsr boollt");
return; return;
} }
/* Direct code only for unsigned data types */
if (flags & CF_UNSIGNED) { if (flags & CF_UNSIGNED) {
unsigned L = GetLocalLabel(); /* Unsigned compare */
AddCodeLine ("cpx #$%02X", (unsigned char)(val >> 8)); /* If the low byte is zero, we must only test the high
AddCodeLine ("bne %s", LocalLabelName (L)); * byte. Or, citing Piotr Fusik:
AddCodeLine ("cmp #$%02X", (unsigned char)val); * Another interpretation: the code is effectively:
g_defcodelabel (L); * if (ax >= 0xAB00) goto L2;
* It's equivalent to:
* if ((ax >> 8) >= 0xAB) goto L2;
*/
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 boolult"); AddCodeLine ("jsr boolult");
return; return;
} } else {
/* Signed compare */
if ((val & 0xFF) == 0) {
AddCodeLine ("cpx #$%02X", (unsigned char)(val >> 8));
AddCodeLine ("jsr boollt");
return;
}
}
break; break;
case CF_LONG: case CF_LONG:
@@ -3426,26 +3444,30 @@ void g_le (unsigned flags, unsigned long val)
*/ */
if (flags & CF_CONST) { if (flags & CF_CONST) {
/* <= is not very effective on the 6502, so try to convert
* it into < if the value is in a valid range.
*/
/* Look at the type */ /* Look at the type */
switch (flags & CF_TYPE) { switch (flags & CF_TYPE) {
case CF_CHAR: case CF_CHAR:
if (flags & CF_FORCECHAR) { if (flags & CF_FORCECHAR) {
if (flags & CF_UNSIGNED) { if (flags & CF_UNSIGNED) {
/* Unsigned compare */
if (val < 255) { if (val < 255) {
AddCodeLine ("cmp #$%02X", (unsigned char)val+1); /* Use < instead of <= because the former gives
* better code on the 6502 than the latter.
*/
AddCodeLine ("cmp #$%02X", (unsigned char)(val+1));
AddCodeLine ("jsr boolult"); AddCodeLine ("jsr boolult");
} else { } else {
AddCodeLine ("cmp #$%02X", (unsigned char)val); AddCodeLine ("cmp #$%02X", (unsigned char)val);
AddCodeLine ("jsr boolule"); AddCodeLine ("jsr boolule");
} }
} else { } else {
/* Signed compare */
if (val < 127) { if (val < 127) {
AddCodeLine ("cmp #$%02X", (unsigned char)val+1); /* Use < instead of <= because the former gives
* better code on the 6502 than the latter.
*/
AddCodeLine ("cmp #$%02X", (unsigned char)(val+1));
AddCodeLine ("jsr boollt"); AddCodeLine ("jsr boollt");
} else { } else {
AddCodeLine ("cmp #$%02X", (unsigned char)val); AddCodeLine ("cmp #$%02X", (unsigned char)val);
@@ -3458,18 +3480,27 @@ void g_le (unsigned flags, unsigned long val)
case CF_INT: case CF_INT:
if (flags & CF_UNSIGNED) { if (flags & CF_UNSIGNED) {
unsigned L = GetLocalLabel(); /* Unsigned compare */
const char* Name = "boolule";
if (val < 65535) { if (val < 65535) {
++val; /* Use < instead of <= because the former gives
Name = "boolult"; * better code on the 6502 than the latter.
*/
g_lt (flags, val+1);
} else {
unsigned L = GetLocalLabel();
AddCodeLine ("cpx #$%02X", (unsigned char)(val >> 8));
AddCodeLine ("bne %s", LocalLabelName (L));
AddCodeLine ("cmp #$%02X", (unsigned char)val);
g_defcodelabel (L);
AddCodeLine ("jsr %s", "boolule");
} }
AddCodeLine ("cpx #$%02X", (unsigned char)(val >> 8));
AddCodeLine ("bne %s", LocalLabelName (L));
AddCodeLine ("cmp #$%02X", (unsigned char)val);
g_defcodelabel (L);
AddCodeLine ("jsr %s", Name);
return; return;
} else {
/* Signed compare */
if (val < 32767) {
g_lt (flags, val+1);
return;
}
} }
break; break;
@@ -3509,34 +3540,36 @@ void g_gt (unsigned flags, unsigned long val)
*/ */
if (flags & CF_CONST) { if (flags & CF_CONST) {
/* > is not very effective on the 6502, so try to convert
* it into >= if the value is in a valid range.
*/
/* Look at the type */ /* Look at the type */
switch (flags & CF_TYPE) { switch (flags & CF_TYPE) {
case CF_CHAR: case CF_CHAR:
if (flags & CF_FORCECHAR) { if (flags & CF_FORCECHAR) {
if (flags & CF_UNSIGNED) { if (flags & CF_UNSIGNED) {
/* If we have a compare > 0, we will replace it by
* != 0 here, since both are identical but the latter
* is easier to optimize.
*/
if (val == 0) { if (val == 0) {
AddCodeLine ("cmp #$%02X", (unsigned char)val); /* If we have a compare > 0, we will replace it by
* != 0 here, since both are identical but the
* latter is easier to optimize.
*/
AddCodeLine ("cmp #$%02X", (unsigned char)val);
AddCodeLine ("jsr boolne"); AddCodeLine ("jsr boolne");
} else if (val < 255) { } else if (val < 255) {
AddCodeLine ("cmp #$%02X", (unsigned char)val+1); /* Use >= instead of > because the former gives
* better code on the 6502 than the latter.
*/
AddCodeLine ("cmp #$%02X", (unsigned char)(val+1));
AddCodeLine ("jsr booluge"); AddCodeLine ("jsr booluge");
} else { } else {
AddCodeLine ("cmp #$%02X", (unsigned char)val); AddCodeLine ("cmp #$%02X", (unsigned char)val);
AddCodeLine ("jsr boolugt"); AddCodeLine ("jsr boolugt");
} }
} else { } else {
if (val < 127) { if (val < 127) {
AddCodeLine ("cmp #$%02X", (unsigned char)val+1); /* Use >= instead of > because the former gives
AddCodeLine ("jsr boolge"); * better code on the 6502 than the latter.
*/
AddCodeLine ("cmp #$%02X", (unsigned char)(val+1));
AddCodeLine ("jsr boolge");
} else { } else {
AddCodeLine ("cmp #$%02X", (unsigned char)val); AddCodeLine ("cmp #$%02X", (unsigned char)val);
AddCodeLine ("jsr boolgt"); AddCodeLine ("jsr boolgt");
@@ -3548,29 +3581,36 @@ void g_gt (unsigned flags, unsigned long val)
case CF_INT: case CF_INT:
if (flags & CF_UNSIGNED) { if (flags & CF_UNSIGNED) {
/* If we have a compare > 0, we will replace it by /* Unsigned compare */
* != 0 here, since both are identical but the latter
* is easier to optimize.
*/
if (val == 0) { if (val == 0) {
/* If we have a compare > 0, we will replace it by
* != 0 here, since both are identical but the latter
* is easier to optimize.
*/
AddCodeLine ("stx tmp1"); AddCodeLine ("stx tmp1");
AddCodeLine ("ora tmp1"); AddCodeLine ("ora tmp1");
AddCodeLine ("jsr boolne"); AddCodeLine ("jsr boolne");
} else { } else if (val < 65535U) {
/* Use >= instead of > because the former gives better
* code on the 6502 than the latter.
*/
g_ge (flags, val+1);
} else {
unsigned L = GetLocalLabel(); unsigned L = GetLocalLabel();
const char* Name = "boolugt";
if (val < 65535) {
++val;
Name = "booluge";
}
AddCodeLine ("cpx #$%02X", (unsigned char)(val >> 8)); AddCodeLine ("cpx #$%02X", (unsigned char)(val >> 8));
AddCodeLine ("bne %s", LocalLabelName (L)); AddCodeLine ("bne %s", LocalLabelName (L));
AddCodeLine ("cmp #$%02X", (unsigned char)val); AddCodeLine ("cmp #$%02X", (unsigned char)val);
g_defcodelabel (L); g_defcodelabel (L);
AddCodeLine ("jsr %s", Name); AddCodeLine ("jsr %s", "boolugt");
} }
return; return;
} } else {
/* Signed compare */
if (val < 32767) {
g_ge (flags, val+1);
return;
}
}
break; break;
case CF_LONG: case CF_LONG:
@@ -3612,6 +3652,8 @@ void g_ge (unsigned flags, unsigned long val)
/* Give a warning in some special cases */ /* Give a warning in some special cases */
if ((flags & CF_UNSIGNED) && val == 0) { if ((flags & CF_UNSIGNED) && val == 0) {
Warning ("Condition is always true"); Warning ("Condition is always true");
AddCodeLine ("jsr return1");
return;
} }
/* Look at the type */ /* Look at the type */
@@ -3640,14 +3682,30 @@ void g_ge (unsigned flags, unsigned long val)
} }
/* Direct code only for unsigned data types */ /* Direct code only for unsigned data types */
if (flags & CF_UNSIGNED) { if (flags & CF_UNSIGNED) {
unsigned L = GetLocalLabel(); /* If the low byte is zero, we must only test the high
AddCodeLine ("cpx #$%02X", (unsigned char)(val >> 8)); * byte. Or, citing Piotr Fusik:
AddCodeLine ("bne %s", LocalLabelName (L)); * Another interpretation: the code is effectively:
AddCodeLine ("cmp #$%02X", (unsigned char)val); * if (ax >= 0xAB00) goto L2;
g_defcodelabel (L); * It's equivalent to:
* if ((ax >> 8) >= 0xAB) goto L2;
*/
AddCodeLine ("cpx #$%02X", (unsigned char)(val >> 8));
if ((val & 0xFF) != 0) {
unsigned L = GetLocalLabel();
AddCodeLine ("bne %s", LocalLabelName (L));
AddCodeLine ("cmp #$%02X", (unsigned char)val);
g_defcodelabel (L);
}
AddCodeLine ("jsr booluge"); AddCodeLine ("jsr booluge");
return; return;
} } else {
/* Signed compare */
if ((val & 0xFF) == 0) {
AddCodeLine ("cpx #$%02X", (unsigned char) (val >> 8));
AddCodeLine ("jsr boolge");
return;
}
}
break; break;
case CF_LONG: case CF_LONG: