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Added optimization for g_inc and g_dec (remove handling of high byte if

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not used).


git-svn-id: svn://svn.cc65.org/cc65/trunk@680 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
cuz 2001-03-27 22:52:16 +00:00
parent e07945e9fc
commit 8e5d8b9e4f
2 changed files with 103 additions and 29 deletions
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33
src/cc65/codegen.c
View File

@ -3367,6 +3367,8 @@ void g_dec (unsigned flags, unsigned long val)
/* FALLTHROUGH */
case CF_INT:
if (CodeSizeFactor < 200) {
/* Use subroutines */
if (val <= 8) {
AddCodeLine ("\tjsr\tdecax%d", (int) val);
} else if (val <= 255) {
@ -3375,6 +3377,37 @@ void g_dec (unsigned flags, unsigned long val)
} else {
g_sub (flags | CF_CONST, val);
}
} else {
/* Inline the code */
if (val < 0x300) {
if ((val & 0xFF) != 0) {
AddCodeLine ("\tsec");
AddCodeLine ("\tsbc\t#$%02X", (unsigned char) val);
AddCodeLine ("\tbcs\t*+3");
AddCodeLine ("\tdex");
/* Tell the optimizer that the X register may be invalid */
AddCodeHint ("x:!");
}
if (val >= 0x100) {
AddCodeLine ("\tdex");
}
if (val >= 0x200) {
AddCodeLine ("\tdex");
}
} else {
AddCodeLine ("\tsec");
if ((val & 0xFF) != 0) {
AddCodeLine ("\tsbc\t#$%02X", (unsigned char) val);
/* Tell the optimizer that the X register may be invalid */
AddCodeHint ("x:!");
}
AddCodeLine ("\tpha");
AddCodeLine ("\ttxa");
AddCodeLine ("\tsbc\t#$%02X", (unsigned char) (val >> 8));
AddCodeLine ("\ttax");
AddCodeLine ("\tpla");
}
}
break;
case CF_LONG:

41
src/cc65/optimize.c
View File

@ -1762,8 +1762,49 @@ static void OptLoads (void)
/* Remove the remaining line */
FreeLine (L2[1]);
/* Search for
*
* adc #xx
* bcc *+3
* inx
*
* Remove the handling of the high byte if the X register
* is not used any more
*/
} else if (LineMatch (L, "\tadc\t#") &&
GetNextCodeLines (L, L2, 3) &&
LineFullMatch (L2[0], "\tbcc\t*+3") &&
LineFullMatch (L2[1], "\tinx") &&
L2[1]->Next &&
IsHint (L2[1]->Next, "x:!") &&
!RegXUsed (L2[1])) {
/* Delete the lines */
FreeLines (L2[0], L2[1]->Next);
/* Search for
*
* sbc #xx
* bcs *+3
* dex
*
* Remove the handling of the high byte if the X register
* is not used any more
*/
} else if (LineMatch (L, "\tsbc\t#") &&
GetNextCodeLines (L, L2, 3) &&
LineFullMatch (L2[0], "\tbcs\t*+3") &&
LineFullMatch (L2[1], "\tdex") &&
L2[1]->Next &&
IsHint (L2[1]->Next, "x:!") &&
!RegXUsed (L2[1])) {
/* Delete the lines */
FreeLines (L2[0], L2[1]->Next);
}
/* All other patterns start with this one: */
if (!LineFullMatch (L, "\tldx\t#$00")) {
/* Next line */