1 /*****************************************************************************/
5 /* Parse the switch statement */
9 /* (C) 1998-2002 Ullrich von Bassewitz */
11 /* D-70597 Stuttgart */
12 /* EMail: uz@cc65.org */
15 /* This software is provided 'as-is', without any expressed or implied */
16 /* warranty. In no event will the authors be held liable for any damages */
17 /* arising from the use of this software. */
19 /* Permission is granted to anyone to use this software for any purpose, */
20 /* including commercial applications, and to alter it and redistribute it */
21 /* freely, subject to the following restrictions: */
23 /* 1. The origin of this software must not be misrepresented; you must not */
24 /* claim that you wrote the original software. If you use this software */
25 /* in a product, an acknowledgment in the product documentation would be */
26 /* appreciated but is not required. */
27 /* 2. Altered source versions must be plainly marked as such, and must not */
28 /* be misrepresented as being the original software. */
29 /* 3. This notice may not be removed or altered from any source */
32 /*****************************************************************************/
58 /*****************************************************************************/
60 /*****************************************************************************/
64 void SwitchStatement (void)
65 /* Handle a switch statement for chars with a cmp cascade for the selector */
67 Collection* Nodes; /* CaseNode tree */
68 ExprDesc SwitchExpr; /* Switch statement expression */
69 ExprDesc CaseExpr; /* Case label expression */
70 type SwitchExprType; /* Basic switch expression type */
71 CodeMark CaseCodeStart; /* Start of code marker */
72 unsigned Depth; /* Number of bytes the selector type has */
73 unsigned ExitLabel; /* Exit label */
74 unsigned CaseLabel; /* Label for case */
75 unsigned DefaultLabel; /* Label for the default branch */
76 long Val; /* Case label value */
77 int HaveBreak = 0; /* True if the last statement had a break */
80 /* Eat the "switch" token */
83 /* Read the switch expression */
85 intexpr (&SwitchExpr);
88 /* Opening curly brace */
91 /* Remember the current code position */
92 CaseCodeStart = GetCodePos();
94 /* Get the unqualified type of the switch expression */
95 SwitchExprType = UnqualifiedType (SwitchExpr.Type[0]);
97 /* Get the number of bytes the selector type has */
98 Depth = SizeOf (SwitchExpr.Type);
99 CHECK (Depth == 1 || Depth == 2 || Depth == 4);
101 /* Get the exit label for the switch statement */
102 ExitLabel = GetLocalLabel ();
104 /* Create a loop so we may use break. */
105 AddLoop (oursp, 0, ExitLabel, 0, 0);
107 /* Create the collection for the case node tree */
108 Nodes = NewCollection ();
110 /* Clear the label for the default branch */
113 /* Parse the labels */
114 while (CurTok.Tok != TOK_RCURLY) {
116 while (CurTok.Tok == TOK_CASE || CurTok.Tok == TOK_DEFAULT) {
118 /* Parse the selector */
119 if (CurTok.Tok == TOK_CASE) {
121 /* Skip the "case" token */
124 /* Read the selector expression */
125 ConstExpr (&CaseExpr);
126 if (!IsClassInt (CaseExpr.Type)) {
127 Error ("Switch quantity not an integer");
130 /* Check the range of the expression */
131 Val = CaseExpr.ConstVal;
132 switch (SwitchExprType) {
136 if (Val < -128 || Val > 127) {
137 Error ("Range error");
142 if (Val < 0 || Val > 255) {
143 Error ("Range error");
149 if (Val < -32768 || Val > 32767) {
150 Error ("Range error");
156 if (Val < 0 || Val > 65535) {
157 Error ("Range error");
166 Internal ("Invalid type: %04X", SwitchExprType);
169 /* Insert the case selector into the selector table */
170 CaseLabel = InsertCaseValue (Nodes, Val, Depth);
172 /* Define this label */
173 g_defcodelabel (CaseLabel);
183 /* Check if we do already have a default branch */
184 if (DefaultLabel == 0) {
186 /* Generate and emit the default label */
187 DefaultLabel = GetLocalLabel ();
188 g_defcodelabel (DefaultLabel);
191 /* We had the default label already */
192 Error ("Duplicate `default' case");
202 /* Parse statements */
203 if (CurTok.Tok != TOK_RCURLY) {
204 HaveBreak = Statement (0);
208 /* Check if we had any labels */
209 if (CollCount (Nodes) == 0 && DefaultLabel == 0) {
211 Warning ("No case labels");
215 CodeMark SwitchCodeStart;
217 /* If the last statement did not have a break, we may have an open
218 * label (maybe from an if or similar). Emitting code and then moving
219 * this code to the top will also move the label to the top which is
220 * wrong. So if the last statement did not have a break (which would
221 * carry the label), add a jump to the exit. If it is useless, the
222 * optimizer will remove it later.
228 /* Remember the current position */
229 SwitchCodeStart = GetCodePos();
232 g_switch (Nodes, DefaultLabel? DefaultLabel : ExitLabel, Depth);
234 /* Move the code to the front */
235 MoveCode (SwitchCodeStart, GetCodePos(), CaseCodeStart);
239 /* Define the exit label */
240 g_defcodelabel (ExitLabel);
242 /* Eat the closing curly brace */
245 /* Free the case value tree */
246 FreeCaseNodeColl (Nodes);