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Added SBC optimizations suggested by Piotr Fusik

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git-svn-id: svn://svn.cc65.org/cc65/trunk@1123 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
cuz
2001-11-17 11:31:57 +00:00
parent b8facd7f1e
commit 2de4a26251
1 changed files with 16 additions and 19 deletions
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35
src/cc65/codegen.c
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@@ -1748,11 +1748,10 @@ 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 #$FF");
AddCodeLine ("sec"); AddCodeLine ("sec");
AddCodeLine ("sta tmp1"); AddCodeLine ("adc %s", lbuf);
AddCodeLine ("lda %s", lbuf);
AddCodeLine ("sbc tmp1");
AddCodeLine ("sta %s", lbuf); AddCodeLine ("sta %s", lbuf);
} }
if ((flags & CF_UNSIGNED) == 0) { if ((flags & CF_UNSIGNED) == 0) {
@@ -1784,14 +1783,13 @@ void g_subeqstatic (unsigned flags, unsigned long label, long offs,
AddCodeLine ("tax"); AddCodeLine ("tax");
AddCodeLine ("lda %s", lbuf); AddCodeLine ("lda %s", lbuf);
} }
} else { } else {
AddCodeLine ("sta tmp1"); AddCodeLine ("eor #$FF");
AddCodeLine ("lda %s", lbuf); AddCodeLine ("adc %s", lbuf);
AddCodeLine ("sbc tmp1");
AddCodeLine ("sta %s", lbuf); AddCodeLine ("sta %s", lbuf);
AddCodeLine ("stx tmp1"); AddCodeLine ("txa");
AddCodeLine ("lda %s+1", lbuf); AddCodeLine ("eor #$FF");
AddCodeLine ("sbc tmp1"); AddCodeLine ("adc %s+1", lbuf);
AddCodeLine ("sta %s+1", lbuf); AddCodeLine ("sta %s+1", lbuf);
AddCodeLine ("tax"); AddCodeLine ("tax");
AddCodeLine ("lda %s", lbuf); AddCodeLine ("lda %s", lbuf);
@@ -1845,18 +1843,17 @@ void g_subeqlocal (unsigned flags, int offs, unsigned long val)
AddCodeLine ("lda (sp),y"); AddCodeLine ("lda (sp),y");
AddCodeLine ("sbc #$%02X", (unsigned char)val); AddCodeLine ("sbc #$%02X", (unsigned char)val);
} else { } else {
AddCodeLine ("sta tmp1"); AddCodeLine ("eor #$FF");
AddCodeLine ("lda (sp),y"); AddCodeLine ("adc (sp),y");
AddCodeLine ("sbc tmp1");
} }
AddCodeLine ("sta (sp),y"); AddCodeLine ("sta (sp),y");
if ((flags & CF_UNSIGNED) == 0) { if ((flags & CF_UNSIGNED) == 0) {
unsigned L = GetLocalLabel(); unsigned L = GetLocalLabel();
AddCodeLine ("bpl %s", LocalLabelName (L)); AddCodeLine ("bpl %s", LocalLabelName (L));
AddCodeLine ("dex"); AddCodeLine ("dex");
g_defcodelabel (L); g_defcodelabel (L);
} }
break; break;
} }
/* FALLTHROUGH */ /* FALLTHROUGH */