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Almost fixed Issue #169. The only denominator not working right now is -2147483648.

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This commit is contained in:
acqn 2020-07-02 10:30:02 +08:00 committed by Oliver Schmidt
parent 82c8bd6e2b
commit e98fe04cc2
1 changed files with 60 additions and 42 deletions
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102
src/cc65/codegen.c
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@ -1479,48 +1479,9 @@ void g_scale (unsigned flags, long val)
/* Scale down */
val = -val;
if ((p2 = PowerOf2 (val)) > 0 && p2 <= 4) {
/* Factor is 2, 4, 8 and 16 use special function */
switch (flags & CF_TYPEMASK) {
case CF_CHAR:
if (flags & CF_FORCECHAR) {
if (flags & CF_UNSIGNED) {
while (p2--) {
AddCodeLine ("lsr a");
}
break;
} else if (p2 <= 2) {
AddCodeLine ("cmp #$80");
AddCodeLine ("ror a");
break;
}
}
/* FALLTHROUGH */
case CF_INT:
if (flags & CF_UNSIGNED) {
AddCodeLine ("jsr lsrax%d", p2);
} else {
AddCodeLine ("jsr asrax%d", p2);
}
break;
case CF_LONG:
if (flags & CF_UNSIGNED) {
AddCodeLine ("jsr lsreax%d", p2);
} else {
AddCodeLine ("jsr asreax%d", p2);
}
break;
default:
typeerror (flags);
}
} else if (val != 1) {
/* g_div will use asr if feasible */
if (val != 1) {
/* Use a division instead */
g_div (flags | CF_CONST, val);
@ -2668,11 +2629,52 @@ void g_div (unsigned flags, unsigned long val)
"tosdivax", "tosudivax", "tosdiveax", "tosudiveax"
};
unsigned DoShiftLabel, EndLabel;
/* Do strength reduction if the value is constant and a power of two */
int p2;
if ((flags & CF_CONST) && (p2 = PowerOf2 (val)) >= 0) {
/* Generate a shift instead */
g_asr (flags, p2);
if (flags & CF_UNSIGNED) {
g_asr (flags, p2);
} else if (p2 > 0) {
/* GitHub #169 - if abs(expr) < abs(val), the result is always 0 */
DoShiftLabel = GetLocalLabel ();
EndLabel = GetLocalLabel ();
switch (flags & CF_TYPEMASK) {
case CF_CHAR:
if (flags & CF_FORCECHAR) {
AddCodeLine ("cmp #$00");
AddCodeLine ("bpl %s", LocalLabelName (DoShiftLabel));
break;
}
/* FALLTHROUGH */
case CF_INT:
AddCodeLine ("cpx #$00");
AddCodeLine ("bpl %s", LocalLabelName (DoShiftLabel));
break;
case CF_LONG:
AddCodeLine ("ldy sreg+1");
AddCodeLine ("bpl %s", LocalLabelName (DoShiftLabel));
break;
default:
typeerror (flags);
break;
}
g_save (flags);
g_le (flags, (unsigned long)-(signed long)val);
AddCodeLine ("lsr a");
g_restore (flags);
AddCodeLine ("bcs %s", LocalLabelName (DoShiftLabel));
g_getimmed (flags | CF_ABSOLUTE, 0, 0);
g_jump (EndLabel);
g_defcodelabel (DoShiftLabel);
g_asr (flags, p2);
g_defcodelabel (EndLabel);
}
} else {
/* Generate a division */
if (flags & CF_CONST) {
@ -2956,6 +2958,22 @@ void g_asr (unsigned flags, unsigned long val)
switch (flags & CF_TYPEMASK) {
case CF_CHAR:
if (flags & CF_FORCECHAR) {
if ((flags & CF_UNSIGNED) != 0 && val <= 4) {
while (val--) {
AddCodeLine ("lsr a");
}
return;
} else if (val <= 2) {
while (val--) {
AddCodeLine ("cmp #$80");
AddCodeLine ("ror a");
}
return;
}
}
/* FALLTHROUGH */
case CF_INT:
val &= 0x0F;
if (val >= 8) {