mirror of https://github.com/cc65/cc65.git
285 lines
11 KiB
C
285 lines
11 KiB
C
/*****************************************************************************/
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/* */
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/* loadexpr.c */
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/* */
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/* Load an expression into the primary register */
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/* */
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/* */
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/* */
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/* (C) 2004-2009, 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 "exprdesc.h"
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#include "global.h"
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#include "loadexpr.h"
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/*****************************************************************************/
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/* Code */
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/*****************************************************************************/
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static void LoadAddress (unsigned Flags, ExprDesc* Expr)
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/* Load the primary register with some address value. */
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{
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switch (ED_GetLoc (Expr)) {
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case E_LOC_ABS:
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/* Numberic address */
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g_getimmed (Flags | CF_IMM | CF_CONST, Expr->IVal, 0);
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break;
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case E_LOC_GLOBAL:
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/* Global symbol, load address */
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g_getimmed ((Flags | CF_EXTERNAL) & ~CF_CONST, Expr->Name, Expr->IVal);
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break;
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case E_LOC_STATIC:
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/* Static symbol, load address */
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g_getimmed ((Flags | CF_STATIC) & ~CF_CONST, Expr->Name, Expr->IVal);
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break;
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case E_LOC_LITERAL:
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/* Literal, load address */
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g_getimmed ((Flags | CF_LITERAL) & ~CF_CONST, Expr->Name, Expr->IVal);
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break;
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case E_LOC_REGISTER:
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/* Register variable. Taking the address is usually not
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** allowed.
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*/
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if (IS_Get (&AllowRegVarAddr) == 0) {
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Error ("Cannot take the address of a register variable");
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}
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g_getimmed ((Flags | CF_REGVAR) & ~CF_CONST, Expr->Name, Expr->IVal);
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break;
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case E_LOC_CODE:
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/* Code label, load address */
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g_getimmed ((Flags | CF_CODE) & ~CF_CONST, Expr->Name, Expr->IVal);
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break;
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case E_LOC_STACK:
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g_leasp (Expr->IVal);
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break;
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case E_LOC_EXPR:
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if (Expr->IVal != 0) {
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/* We have an expression in the primary plus a constant
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** offset. Adjust the value in the primary accordingly.
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*/
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g_inc (Flags | CF_CONST, Expr->IVal);
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}
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break;
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default:
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Internal ("Unknown address type: %04X", Expr->Flags);
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}
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}
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void LoadExpr (unsigned Flags, struct ExprDesc* Expr)
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/* Load an expression into the primary register if it is not already there.
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** If Flags contains any CF_TYPEMASK bits, it then overrides the codegen type
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** info that would be otherwise taken from the expression type.
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** Note: This function can't modify the content in Expr since there are many
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** instances of the "GetCodePos + LoadExpr (maybe indirectly) + RemoveCode"
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** code pattern here and there which assumes that Expr should be unchanged,
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** unfortunately.
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*/
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{
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if (!ED_IsAddrExpr (Expr)) {
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/* Lvalue. If this is a bit field its type is unsigned. But if the
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** field is completely contained in the lower byte, we will throw away
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** the high byte anyway and may therefore load just the low byte.
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*/
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int AdjustBitField = 0;
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unsigned BitFieldFullWidthFlags = 0;
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if ((Flags & CF_TYPEMASK) == 0) {
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if (IsTypeFragBitField (Expr->Type)) {
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/* We need to adjust the bits in this case. */
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AdjustBitField = 1;
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/* Flags we need operate on the whole bit-field, without CF_FORCECHAR. */
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BitFieldFullWidthFlags = Flags | TypeOf (Expr->Type);
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/* Flags we need operate on the whole chunk containing the bit-field. */
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Flags |= TypeOf (GetBitFieldChunkType (Expr->Type));
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/* If we're adjusting, then only load a char (not an int) and do only char ops;
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** We will clear the high byte in the adjustment. CF_FORCECHAR does nothing if
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** the type is not CF_CHAR;
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** If adjusting, then we're sign extending manually, so do everything unsigned
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** to make shifts faster.
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*/
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Flags |= CF_UNSIGNED | CF_FORCECHAR;
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BitFieldFullWidthFlags |= CF_UNSIGNED;
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} else {
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/* If Expr is an incomplete ESY type, bail out */
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if (IsIncompleteESUType (Expr->Type)) {
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return;
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}
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Flags |= TypeOf (Expr->Type);
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}
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}
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if (ED_YetToTest (Expr)) {
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/* If we're only testing, we do not need to promote char to int.
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** CF_FORCECHAR does nothing if the type is not CF_CHAR.
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*/
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Flags |= CF_FORCECHAR;
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/* Setting CF_TEST will cause the load to perform optimizations and not actually load
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** all bits of the bit-field, instead just computing the condition codes. Therefore,
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** if adjustment is required, we do not set CF_TEST here, but handle it below.
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*/
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if (!AdjustBitField) {
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Flags |= CF_TEST;
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}
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}
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/* Load the content of Expr */
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switch (ED_GetLoc (Expr)) {
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case E_LOC_NONE:
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/* Immediate number constant */
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g_getimmed (Flags | CF_IMM | TypeOf (Expr->Type) | CF_CONST, Expr->IVal, 0);
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break;
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case E_LOC_ABS:
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/* Absolute numeric addressed variable */
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g_getstatic (Flags | CF_ABSOLUTE, Expr->IVal, 0);
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break;
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case E_LOC_GLOBAL:
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/* Global variable */
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g_getstatic (Flags | CF_EXTERNAL, Expr->Name, Expr->IVal);
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break;
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case E_LOC_STATIC:
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/* Static variable */
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g_getstatic (Flags | CF_STATIC, Expr->Name, Expr->IVal);
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break;
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case E_LOC_LITERAL:
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/* Literal in the literal pool */
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g_getstatic (Flags | CF_LITERAL, Expr->Name, Expr->IVal);
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break;
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case E_LOC_REGISTER:
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/* Register variable */
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g_getstatic (Flags | CF_REGVAR, Expr->Name, Expr->IVal);
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break;
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case E_LOC_CODE:
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/* Code label location */
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g_getstatic (Flags | CF_CODE, Expr->Name, Expr->IVal);
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break;
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case E_LOC_STACK:
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/* Value on the stack */
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g_getlocal (Flags, Expr->IVal);
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break;
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case E_LOC_PRIMARY:
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/* The primary register */
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if (Expr->IVal != 0) {
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/* We have an expression in the primary plus a constant
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** offset. Adjust the value in the primary accordingly.
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*/
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g_inc (Flags | CF_CONST, Expr->IVal);
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/* We might want to clear the offset, but we can't */
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}
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if (Flags & CF_TEST) {
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g_test (Flags);
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}
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break;
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case E_LOC_EXPR:
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/* Reference to address in primary with offset in Expr */
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g_getind (Flags, Expr->IVal);
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/* Since the content in primary is now overwritten with the
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** dereference value, we might want to change the expression
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** loc to E_LOC_PRIMARY as well. That way we could be able to
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** call this function as many times as we want. Unfortunately,
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** we can't.
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*/
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break;
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default:
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Internal ("Invalid location in LoadExpr: 0x%04X", ED_GetLoc (Expr));
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}
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/* Handle bit fields if necessary. The actual type may have been casted or converted,
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** so be sure to always use unsigned ints for the operations.
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*/
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if (AdjustBitField) {
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/* We always need to do something with the low byte, so there is no opportunity
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** for optimization by skipping it.
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*/
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CHECK (Expr->Type->A.B.Offs < CHAR_BITS);
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if (ED_YetToTest (Expr)) {
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g_testbitfield (Flags, Expr->Type->A.B.Offs, Expr->Type->A.B.Width);
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} else {
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g_extractbitfield (Flags, BitFieldFullWidthFlags, IsSignSigned (Expr->Type),
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Expr->Type->A.B.Offs, Expr->Type->A.B.Width);
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}
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}
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/* Expression was tested */
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ED_TestDone (Expr);
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} else {
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/* An address */
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Flags |= CF_INT | CF_UNSIGNED;
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/* Constant of some sort, load it into the primary */
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LoadAddress (Flags, Expr);
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/* Are we testing this value? */
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if (ED_YetToTest (Expr)) {
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/* Yes, force a test */
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g_test (Flags);
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ED_TestDone (Expr);
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}
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}
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if (ED_IsLVal (Expr) && IsQualVolatile (Expr->Type)) {
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/* Expression has had side effects */
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Expr->Flags |= E_SIDE_EFFECTS;
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}
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}
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