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Better code for compares

git-svn-id: svn://svn.cc65.org/cc65/trunk@1152 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
cuz 2002-02-13 10:42:56 +00:00
parent b8c4dc9b06
commit 18b591e268

View File

@ -3298,11 +3298,11 @@ void g_ne (unsigned flags, unsigned long val)
/* FALLTHROUGH */
case CF_INT:
L = GetLocalLabel();
L = GetLocalLabel();
AddCodeLine ("cpx #$%02X", (unsigned char)(val >> 8));
AddCodeLine ("bne %s", LocalLabelName (L));
AddCodeLine ("cmp #$%02X", (unsigned char)val);
g_defcodelabel (L);
g_defcodelabel (L);
AddCodeLine ("jsr boolne");
return;
@ -3364,23 +3364,9 @@ void g_lt (unsigned flags, unsigned long val)
/* FALLTHROUGH */
case CF_INT:
if ((flags & CF_UNSIGNED) == 0 && val == 0) {
/* If we have a signed compare against zero, we only need to
* test the high byte.
*/
AddCodeLine ("txa");
AddCodeLine ("jsr boollt");
return;
}
if (flags & CF_UNSIGNED) {
/* Unsigned compare */
/* If the low byte is zero, we must only test the high
* byte. Or, citing Piotr Fusik:
* Another interpretation: the code is effectively:
* if (ax >= 0xAB00) goto L2;
* It's equivalent to:
* if ((ax >> 8) >= 0xAB) goto L2;
*/
/* If the low byte is zero, we must only test the high byte */
AddCodeLine ("cpx #$%02X", (unsigned char)(val >> 8));
if ((val & 0xFF) != 0) {
unsigned L = GetLocalLabel();
@ -3389,16 +3375,20 @@ void g_lt (unsigned flags, unsigned long val)
g_defcodelabel (L);
}
AddCodeLine ("jsr boolult");
return;
} else {
/* Signed compare */
if ((val & 0xFF) == 0) {
AddCodeLine ("cpx #$%02X", (unsigned char)(val >> 8));
AddCodeLine ("jsr boollt");
return;
/* Low byte is zero, just look at the high byte */
AddCodeLine ("cpx #$%02X", (unsigned char)(val >> 8));
} else {
/* Subtract the two values */
AddCodeLine ("cmp #$%02X", (unsigned char)val);
AddCodeLine ("txa");
AddCodeLine ("sbc #$%02X", (unsigned char)(val >> 8));
}
AddCodeLine ("jsr boollt");
}
break;
return;
case CF_LONG:
if ((flags & CF_UNSIGNED) == 0 && val == 0) {
@ -3406,10 +3396,25 @@ void g_lt (unsigned flags, unsigned long val)
* test the high byte.
*/
AddCodeLine ("lda sreg+1");
AddCodeLine ("jsr boollt");
return;
} else {
/* Do a subtraction */
AddCodeLine ("cmp #$%02X", (unsigned char)val);
AddCodeLine ("txa");
AddCodeLine ("sbc #$%02X", (unsigned char)(val >> 8));
AddCodeLine ("lda sreg");
AddCodeLine ("sbc #$%02X", (unsigned char)(val >> 16));
AddCodeLine ("lda sreg+1");
AddCodeLine ("sbc #$%02X", (unsigned char)(val >> 24));
}
break;
/* Emit the proper makebool routine */
if (flags & CF_UNSIGNED) {
/* Unsigned compare */
AddCodeLine ("jsr boolult");
} else {
/* Signed compare */
AddCodeLine ("jsr boollt");
}
return;
default:
typeerror (flags);
@ -3451,27 +3456,27 @@ void g_le (unsigned flags, unsigned long val)
if (flags & CF_FORCECHAR) {
if (flags & CF_UNSIGNED) {
/* Unsigned compare */
if (val < 255) {
if (val < 0xFF) {
/* Use < instead of <= because the former gives
* better code on the 6502 than the latter.
*/
AddCodeLine ("cmp #$%02X", (unsigned char)(val+1));
AddCodeLine ("jsr boolult");
g_lt (flags, val+1);
} else {
AddCodeLine ("cmp #$%02X", (unsigned char)val);
AddCodeLine ("jsr boolule");
/* Always true */
Warning ("Condition is always true");
AddCodeLine ("jsr return1");
}
} else {
/* Signed compare */
if (val < 127) {
if (val < 0x7F) {
/* Use < instead of <= because the former gives
* better code on the 6502 than the latter.
*/
AddCodeLine ("cmp #$%02X", (unsigned char)(val+1));
AddCodeLine ("jsr boollt");
g_lt (flags, val+1);
} else {
AddCodeLine ("cmp #$%02X", (unsigned char)val);
AddCodeLine ("jsr boolle");
/* Always true */
Warning ("Condition is always true");
AddCodeLine ("jsr return1");
}
}
return;
@ -3481,31 +3486,52 @@ void g_le (unsigned flags, unsigned long val)
case CF_INT:
if (flags & CF_UNSIGNED) {
/* Unsigned compare */
if (val < 65535) {
if (val < 0xFFFF) {
/* Use < instead of <= because the former gives
* better code on the 6502 than the latter.
*/
g_lt (flags, val+1);
} else {
unsigned L = GetLocalLabel();
AddCodeLine ("cpx #$%02X", (unsigned char)(val >> 8));
AddCodeLine ("bne %s", LocalLabelName (L));
AddCodeLine ("cmp #$%02X", (unsigned char)val);
g_defcodelabel (L);
AddCodeLine ("jsr %s", "boolule");
/* Always true */
Warning ("Condition is always true");
AddCodeLine ("jsr return1");
}
return;
} else {
/* Signed compare */
if (val < 32767) {
if (val < 0x7FFF) {
g_lt (flags, val+1);
return;
}
} else {
/* Always true */
Warning ("Condition is always true");
AddCodeLine ("jsr return1");
}
}
break;
return;
case CF_LONG:
break;
if (flags & CF_UNSIGNED) {
/* Unsigned compare */
if (val < 0xFFFFFFFF) {
/* Use < instead of <= because the former gives
* better code on the 6502 than the latter.
*/
g_lt (flags, val+1);
} else {
/* Always true */
Warning ("Condition is always true");
AddCodeLine ("jsr return1");
}
} else {
/* Signed compare */
if (val < 0x7FFFFFFF) {
g_lt (flags, val+1);
} else {
/* Always true */
Warning ("Condition is always true");
AddCodeLine ("jsr return1");
}
}
return;
default:
typeerror (flags);
@ -3551,28 +3577,27 @@ void g_gt (unsigned flags, unsigned long val)
* != 0 here, since both are identical but the
* latter is easier to optimize.
*/
AddCodeLine ("cmp #$%02X", (unsigned char)val);
AddCodeLine ("jsr boolne");
} else if (val < 255) {
g_ne (flags, val);
} else if (val < 0xFF) {
/* Use >= instead of > because the former gives
* better code on the 6502 than the latter.
*/
AddCodeLine ("cmp #$%02X", (unsigned char)(val+1));
AddCodeLine ("jsr booluge");
g_ge (flags, val+1);
} else {
AddCodeLine ("cmp #$%02X", (unsigned char)val);
AddCodeLine ("jsr boolugt");
}
/* Never true */
Warning ("Condition is never true");
AddCodeLine ("jsr return0");
}
} else {
if (val < 127) {
if (val < 0x7F) {
/* Use >= instead of > because the former gives
* better code on the 6502 than the latter.
*/
AddCodeLine ("cmp #$%02X", (unsigned char)(val+1));
AddCodeLine ("jsr boolge");
g_ge (flags, val+1);
} else {
AddCodeLine ("cmp #$%02X", (unsigned char)val);
AddCodeLine ("jsr boolgt");
/* Never true */
Warning ("Condition is never true");
AddCodeLine ("jsr return0");
}
}
return;
@ -3587,34 +3612,59 @@ void g_gt (unsigned flags, unsigned long val)
* != 0 here, since both are identical but the latter
* is easier to optimize.
*/
AddCodeLine ("stx tmp1");
AddCodeLine ("ora tmp1");
AddCodeLine ("jsr boolne");
} else if (val < 65535U) {
g_ne (flags, val);
} else if (val < 0xFFFF) {
/* Use >= instead of > because the former gives better
* code on the 6502 than the latter.
*/
g_ge (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", "boolugt");
/* Never true */
Warning ("Condition is never true");
AddCodeLine ("jsr return0");
}
return;
} else {
/* Signed compare */
if (val < 32767) {
if (val < 0x7FFF) {
g_ge (flags, val+1);
return;
}
} else {
/* Never true */
Warning ("Condition is never true");
AddCodeLine ("jsr return0");
}
}
break;
return;
case CF_LONG:
break;
if (flags & CF_UNSIGNED) {
/* Unsigned compare */
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.
*/
g_ne (flags, val);
} else if (val < 0xFFFFFFFF) {
/* Use >= instead of > because the former gives better
* code on the 6502 than the latter.
*/
g_ge (flags, val+1);
} else {
/* Never true */
Warning ("Condition is never true");
AddCodeLine ("jsr return0");
}
} else {
/* Signed compare */
if (val < 0x7FFFFFFF) {
g_ge (flags, val+1);
} else {
/* Never true */
Warning ("Condition is never true");
AddCodeLine ("jsr return0");
}
}
return;
default:
typeerror (flags);
@ -3672,23 +3722,9 @@ void g_ge (unsigned flags, unsigned long val)
/* FALLTHROUGH */
case CF_INT:
if ((flags & CF_UNSIGNED) == 0 && val == 0) {
/* If we have a signed compare against zero, we only need to
* test the high byte.
*/
AddCodeLine ("txa");
AddCodeLine ("jsr boolge");
return;
}
/* Direct code only for unsigned data types */
if (flags & CF_UNSIGNED) {
/* If the low byte is zero, we must only test the high
* byte. Or, citing Piotr Fusik:
* Another interpretation: the code is effectively:
* if (ax >= 0xAB00) goto L2;
* It's equivalent to:
* if ((ax >> 8) >= 0xAB) goto L2;
*/
/* Unsigned compare */
/* If the low byte is zero, we must only test the high byte */
AddCodeLine ("cpx #$%02X", (unsigned char)(val >> 8));
if ((val & 0xFF) != 0) {
unsigned L = GetLocalLabel();
@ -3697,16 +3733,20 @@ void g_ge (unsigned flags, unsigned long val)
g_defcodelabel (L);
}
AddCodeLine ("jsr booluge");
return;
} else {
/* Signed compare */
if ((val & 0xFF) == 0) {
AddCodeLine ("cpx #$%02X", (unsigned char) (val >> 8));
AddCodeLine ("jsr boolge");
return;
/* Low byte is zero, just look at the high byte */
AddCodeLine ("cpx #$%02X", (unsigned char)(val >> 8));
} else {
/* Subtract the two values */
AddCodeLine ("cmp #$%02X", (unsigned char)val);
AddCodeLine ("txa");
AddCodeLine ("sbc #$%02X", (unsigned char)(val >> 8));
}
AddCodeLine ("jsr boolge");
}
break;
return;
case CF_LONG:
if ((flags & CF_UNSIGNED) == 0 && val == 0) {
@ -3714,10 +3754,25 @@ void g_ge (unsigned flags, unsigned long val)
* test the high byte.
*/
AddCodeLine ("lda sreg+1");
AddCodeLine ("jsr boolge");
return;
} else {
/* Do a subtraction */
AddCodeLine ("cmp #$%02X", (unsigned char)val);
AddCodeLine ("txa");
AddCodeLine ("sbc #$%02X", (unsigned char)(val >> 8));
AddCodeLine ("lda sreg");
AddCodeLine ("sbc #$%02X", (unsigned char)(val >> 16));
AddCodeLine ("lda sreg+1");
AddCodeLine ("sbc #$%02X", (unsigned char)(val >> 24));
}
break;
/* Emit the proper makebool routine */
if (flags & CF_UNSIGNED) {
/* Unsigned compare */
AddCodeLine ("jsr booluge");
} else {
/* Signed compare */
AddCodeLine ("jsr boolge");
}
return;
default:
typeerror (flags);