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