1 /*****************************************************************************/
5 /* Parse assignments */
9 /* (C) 2002-2004 Ullrich von Bassewitz */
10 /* Römerstrasse 52 */
11 /* D-70794 Filderstadt */
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 /*****************************************************************************/
37 #include "assignment.h"
49 /*****************************************************************************/
51 /*****************************************************************************/
55 void Assignment (ExprDesc* lval)
56 /* Parse an assignment */
59 type* ltype = lval->Type;
62 /* We must have an lvalue for an assignment */
63 if (ED_IsRVal (lval)) {
64 Error ("Invalid lvalue in assignment");
67 /* Check for assignment to const */
68 if (IsQualConst (ltype)) {
69 Error ("Assignment to const");
72 /* Skip the '=' token */
75 /* cc65 does not have full support for handling structs by value. Since
76 * assigning structs is one of the more useful operations from this
77 * family, allow it here.
79 if (IsClassStruct (ltype)) {
81 /* Get the size of the left hand side. */
82 unsigned Size = SizeOf (ltype);
84 /* If the size is that of a basic type (char, int, long), we will copy
85 * the struct using the primary register, otherwise we use memcpy. In
86 * the former case, push the address only if really needed.
91 case SIZEOF_CHAR: stype = type_uchar; break;
92 case SIZEOF_INT: stype = type_uint; break;
93 case SIZEOF_LONG: stype = type_ulong; break;
94 default: stype = ltype; UseReg = 0; break;
99 ExprLoad (CF_NONE, lval);
100 g_push (CF_PTR | CF_UNSIGNED, 0);
103 /* Get the expression on the right of the '=' into the primary */
106 /* Check for equality of the structs */
107 if (TypeCmp (ltype, lval2.Type) < TC_STRICT_COMPATIBLE) {
108 Error ("Incompatible types");
111 /* Check if the right hand side is an lvalue */
112 if (ED_IsLVal (&lval2)) {
113 /* We have an lvalue. Do we copy using the primary? */
115 /* Just use the replacement type */
118 /* Load the value into the primary */
119 ExprLoad (CF_FORCECHAR, &lval2);
121 /* Store it into the new location */
126 /* We will use memcpy. Push the address of the rhs */
127 ED_MakeRVal (&lval2);
128 ExprLoad (CF_NONE, &lval2);
130 /* Push the address (or whatever is in ax in case of errors) */
131 g_push (CF_PTR | CF_UNSIGNED, 0);
133 /* Load the size of the struct into the primary */
134 g_getimmed (CF_INT | CF_UNSIGNED | CF_CONST, CheckedSizeOf (ltype), 0);
136 /* Call the memcpy function */
137 g_call (CF_FIXARGC, Func_memcpy, 4);
142 /* We have an rvalue. This can only happen if a function returns
143 * a struct, since there is no other way to generate an expression
144 * that as a struct as an rvalue result. We allow only 1, 2, and 4
145 * byte sized structs and do direct assignment.
151 /* Print a diagnostic */
152 Error ("Structs of this size are not supported");
153 /* Adjust the stack so we won't run in an internal error later */
161 /* Get the address on stack if needed */
164 /* Read the expression on the right side of the '=' */
167 /* Do type conversion if necessary */
168 TypeConversion (&lval2, ltype);
170 /* If necessary, load the value into the primary register */
171 ExprLoad (CF_NONE, &lval2);
173 /* Generate a store instruction */
178 /* Value is still in primary and not an lvalue */
179 lval->Flags = E_MEXPR | E_RVAL;