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clearer comments on and usage of code generator flags with type conversions in the primary register.

This commit is contained in:
acqn 2022-11-13 14:57:48 +08:00
parent 6924d44564
commit 3bcfa735cb
2 changed files with 81 additions and 54 deletions
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117
src/cc65/codegen.c
View File

@ -1283,34 +1283,49 @@ void g_tosint (unsigned flags)
static void g_regchar (unsigned Flags)
/* Make sure, the value in the primary register is in the range of char. Truncate if necessary */
static void g_regchar (unsigned to)
/* Treat the value in the primary register as a char with specified signedness
** and convert it to an int (whose representation is irrelevent of signedness).
*/
{
unsigned L;
AddCodeLine ("ldx #$00");
if ((Flags & CF_UNSIGNED) == 0) {
/* Sign extend */
L = GetLocalLabel();
AddCodeLine ("cmp #$80");
AddCodeLine ("bcc %s", LocalLabelName (L));
AddCodeLine ("dex");
g_defcodelabel (L);
}
/* Since char is the smallest type supported here, we never need any info
** about the original type to "promote from it". However, we have to make
** sure the entire AX contains the correct char value as an int, since we
** will almost always use the char value as an int in AX directly in code
** generation (unless CF_FORCECHAR is specified). That is to say, we don't
** need the original "from" flags for the first conversion to char, but do
** need the original "to" flags as the new "from" flags for the conversion
** to int.
*/
g_regint (to | CF_FORCECHAR);
}
void g_regint (unsigned Flags)
/* Make sure, the value in the primary register an int. Convert if necessary */
void g_regint (unsigned from)
/* Convert the value in the primary register to an int (whose representation
** is irrelevent of signedness).
*/
{
switch (Flags & CF_TYPEMASK) {
switch (from & CF_TYPEMASK) {
case CF_CHAR:
if (Flags & CF_FORCECHAR) {
/* Conversion is from char */
g_regchar (Flags);
/* If the original value was forced to use only A, it must be
** extended from char to fill AX. Otherwise nothing to do here
** since AX would already have the correct int value.
*/
if (from & CF_FORCECHAR) {
AddCodeLine ("ldx #$00");
if ((from & CF_UNSIGNED) == 0) {
/* Sign extend */
unsigned L = GetLocalLabel();
AddCodeLine ("cmp #$80");
AddCodeLine ("bcc %s", LocalLabelName (L));
AddCodeLine ("dex");
g_defcodelabel (L);
}
break;
}
/* FALLTHROUGH */
@ -1319,21 +1334,27 @@ void g_regint (unsigned Flags)
break;
default:
typeerror (Flags);
typeerror (from);
}
}
void g_reglong (unsigned Flags)
/* Make sure, the value in the primary register a long. Convert if necessary */
void g_reglong (unsigned from)
/* Convert the value in the primary register to a long (whose representation
** is irrelevent of signedness).
*/
{
switch (Flags & CF_TYPEMASK) {
switch (from & CF_TYPEMASK) {
case CF_CHAR:
if (Flags & CF_FORCECHAR) {
/* If the original value was forced to use only A, it must be
** extended from char to long. Otherwise AX would already have
** the correct int value to be extened to long.
*/
if (from & CF_FORCECHAR) {
/* Conversion is from char */
if (Flags & CF_UNSIGNED) {
if (from & CF_UNSIGNED) {
if (IS_Get (&CodeSizeFactor) >= 200) {
AddCodeLine ("ldx #$00");
AddCodeLine ("stx sreg");
@ -1343,18 +1364,19 @@ void g_reglong (unsigned Flags)
}
} else {
if (IS_Get (&CodeSizeFactor) >= 366) {
g_regchar (Flags);
g_regint (from);
AddCodeLine ("stx sreg");
AddCodeLine ("stx sreg+1");
} else {
AddCodeLine ("jsr along");
}
}
break;
}
/* FALLTHROUGH */
case CF_INT:
if (Flags & CF_UNSIGNED) {
if (from & CF_UNSIGNED) {
if (IS_Get (&CodeSizeFactor) >= 200) {
AddCodeLine ("ldy #$00");
AddCodeLine ("sty sreg");
@ -1371,7 +1393,7 @@ void g_reglong (unsigned Flags)
break;
default:
typeerror (Flags);
typeerror (from);
}
}
@ -1508,48 +1530,49 @@ unsigned g_typeadjust (unsigned lhs, unsigned rhs)
unsigned g_typecast (unsigned lhs, unsigned rhs)
/* Cast the value in the primary register to the operand size that is flagged
** by the lhs value. Return the result value.
unsigned g_typecast (unsigned to, unsigned from)
/* Cast the value in the primary register to the specified operand size and
** signedness. Return the result flags.
*/
{
/* Check if a conversion is needed */
if ((rhs & CF_CONST) == 0) {
switch (lhs & CF_TYPEMASK) {
if ((from & CF_CONST) == 0) {
switch (to & CF_TYPEMASK) {
case CF_LONG:
/* We must promote the primary register to long */
g_reglong (rhs);
/* We must promote the primary register to long in EAX */
g_reglong (from);
break;
case CF_INT:
/* We must promote the primary register to int */
g_regint (rhs);
/* We must promote the primary register to int in AX */
g_regint (from);
break;
case CF_CHAR:
/* We must truncate the primary register to char */
g_regchar (lhs);
/* We must truncate the primary register to char and then
** sign-extend it to signed int in AX.
*/
g_regchar (to);
break;
default:
typeerror (lhs);
/* Since we are switching on "to", report an error on it */
typeerror (to);
}
}
/* Do not need any other action. If the left type is int, and the primary
/* Do not need any other action. If the "to" type is int, and the primary
** register is long, it will be automagically truncated. If the right hand
** side is const, it is not located in the primary register and handled by
** the expression parser code.
*/
/* Result is const if the right hand side was const */
lhs |= (rhs & CF_CONST);
to |= (from & CF_CONST);
/* The resulting type is that of the left hand side (that's why you called
** this function :-)
*/
return lhs;
/* The resulting type is "to" (that's why you called this function :-) */
return to;
}

18
src/cc65/codegen.h
View File

@ -208,11 +208,15 @@ void g_toslong (unsigned flags);
void g_tosint (unsigned flags);
/* Make sure, the value on TOS is an int. Convert if necessary */
void g_regint (unsigned Flags);
/* Make sure, the value in the primary register an int. Convert if necessary */
void g_regint (unsigned from);
/* Convert the value in the primary register to an int (whose representation
** is irrelevent of signedness).
*/
void g_reglong (unsigned Flags);
/* Make sure, the value in the primary register a long. Convert if necessary */
void g_reglong (unsigned from);
/* Convert the value in the primary register to a long (whose representation
** is irrelevent of signedness).
*/
unsigned g_typeadjust (unsigned lhs, unsigned rhs);
/* Adjust the integer operands before doing a binary operation. lhs is a flags
@ -220,9 +224,9 @@ unsigned g_typeadjust (unsigned lhs, unsigned rhs);
** in (e)ax. The return value is the flags value for the resulting type.
*/
unsigned g_typecast (unsigned lhs, unsigned rhs);
/* Cast the value in the primary register to the operand size that is flagged
** by the lhs value. Return the result value.
unsigned g_typecast (unsigned to, unsigned from);
/* Cast the value in the primary register to the specified operand size and
** signedness. Return the result flags.
*/
void g_scale (unsigned flags, long val);