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Allow registers in sweet16 mode also to be specified as constant numbers

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instead of Rx. Suggestion and sample code by Gabriele Galeotti.


git-svn-id: svn://svn.cc65.org/cc65/trunk@3983 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
uz 2009-07-30 13:05:41 +00:00
parent e1866ed9f8
commit a4a1c729c8
1 changed files with 50 additions and 7 deletions
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57
src/ca65/easw16.c
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@ -49,9 +49,31 @@
static long RegNum ()
/* Try to read a register number specified not as a register (Rx) but as a
* numeric value between 0 and 15. Return the register number or -1 on
* failure.
*/
{
long Val;
ExprNode* Expr = Expression ();
if (!IsConstExpr (Expr, &Val) || Val < 0 || Val > 15) {
/* Invalid register */
Val = -1L;
}
/* Free the expression and return the register number */
FreeExpr (Expr);
return Val;
}
void GetSweet16EA (EffAddr* A)
/* Parse an effective address, return the result in A */
{
long Reg;
/* Clear the output struct */
A->AddrModeSet = 0;
A->Expr = 0;
@ -64,15 +86,18 @@ void GetSweet16EA (EffAddr* A)
} else if (Tok == TOK_AT) {
/* @reg */
/* @reg or @regnumber */
A->AddrModeSet = AMSW16_IND;
NextTok ();
if (Tok != TOK_REG) {
ErrorSkip ("Register expected");
A->Reg = 0;
} else {
if (Tok == TOK_REG) {
A->Reg = (unsigned) IVal;
NextTok ();
} else if ((Reg = RegNum ()) >= 0) {
/* Register number */
A->Reg = (unsigned) Reg;
} else {
ErrorSkip ("Register or register number expected");
A->Reg = 0;
}
} else if (Tok == TOK_REG) {
@ -82,7 +107,7 @@ void GetSweet16EA (EffAddr* A)
if (Tok == TOK_COMMA) {
/* Rx, Constant */
/* Rx, constant */
NextTok ();
A->Expr = Expression ();
@ -96,10 +121,28 @@ void GetSweet16EA (EffAddr* A)
} else {
/* OPC ea */
/* OPC ea or: OPC regnum, constant */
A->Expr = Expression ();
A->AddrModeSet = AMSW16_BRA;
/* If the value is a constant between 0 and 15, it may also be a
* register number.
*/
if (IsConstExpr (A->Expr, &Reg) && Reg >= 0 && Reg <= 15) {
FreeExpr (A->Expr);
A->Reg = (unsigned) Reg;
/* If a comma follows, it is: OPC Rx, constant */
if (Tok == TOK_COMMA) {
NextTok ();
A->Expr = Expression ();
A->AddrModeSet = AMSW16_IMM;
} else {
A->Expr = 0;
A->AddrModeSet |= AMSW16_REG;
}
}
}
}