Files
cc65/src/cc65/testexpr.c
cuz 8752f0b2c1 Removed ExprLoad to LoadExpr.
Moved LoadExpr + support functions into a separate module.
Removed obsolete files.
Some cleanup and makefile adjustments.


git-svn-id: svn://svn.cc65.org/cc65/trunk@3113 b7a2c559-68d2-44c3-8de9-860c34a00d81
2004-06-09 14:12:57 +00:00

130 lines
4.7 KiB
C

/*****************************************************************************/
/* */
/* testexpr.c */
/* */
/* Test an expression and jump */
/* */
/* */
/* */
/* (C) 2004 Ullrich von Bassewitz */
/* Römerstraße 52 */
/* D-70794 Filderstadt */
/* EMail: uz@cc65.org */
/* */
/* */
/* This software is provided 'as-is', without any expressed or implied */
/* warranty. In no event will the authors be held liable for any damages */
/* arising from the use of this software. */
/* */
/* Permission is granted to anyone to use this software for any purpose, */
/* including commercial applications, and to alter it and redistribute it */
/* freely, subject to the following restrictions: */
/* */
/* 1. The origin of this software must not be misrepresented; you must not */
/* claim that you wrote the original software. If you use this software */
/* in a product, an acknowledgment in the product documentation would be */
/* appreciated but is not required. */
/* 2. Altered source versions must be plainly marked as such, and must not */
/* be misrepresented as being the original software. */
/* 3. This notice may not be removed or altered from any source */
/* distribution. */
/* */
/*****************************************************************************/
/* cc65 */
#include "codegen.h"
#include "error.h"
#include "expr.h"
#include "loadexpr.h"
#include "scanner.h"
#include "testexpr.h"
/*****************************************************************************/
/* Code */
/*****************************************************************************/
unsigned Test (unsigned Label, int Invert)
/* Evaluate a boolean test expression and jump depending on the result of
* the test and on Invert. The function returns one of the TESTEXPR_xx codes
* defined above. If the jump is always true, a warning is output.
*/
{
ExprDesc Expr;
unsigned Result;
/* Read a boolean expression */
BoolExpr (hie0, &Expr);
/* Check for a constant expression */
if (ED_IsConstAbs (&Expr)) {
/* Result is constant, so we know the outcome */
Result = (Expr.IVal != 0);
/* Constant rvalue */
if (!Invert && Expr.IVal == 0) {
g_jump (Label);
Warning ("Unreachable code");
} else if (Invert && Expr.IVal != 0) {
g_jump (Label);
}
} else {
/* Result is unknown */
Result = TESTEXPR_UNKNOWN;
/* If the expr hasn't set condition codes, set the force-test flag */
if (!ED_IsTested (&Expr)) {
ED_MarkForTest (&Expr);
}
/* Load the value into the primary register */
LoadExpr (CF_FORCECHAR, &Expr);
/* Generate the jump */
if (Invert) {
g_truejump (CF_NONE, Label);
} else {
g_falsejump (CF_NONE, Label);
}
}
/* Return the result */
return Result;
}
unsigned TestInParens (unsigned Label, int Invert)
/* Evaluate a boolean test expression in parenthesis and jump depending on
* the result of the test * and on Invert. The function returns one of the
* TESTEXPR_xx codes defined above. If the jump is always true, a warning is
* output.
*/
{
unsigned Result;
/* Eat the parenthesis */
ConsumeLParen ();
/* Do the test */
Result = Test (Label, Invert);
/* Check for the closing brace */
ConsumeRParen ();
/* Return the result of the expression */
return Result;
}