#include "check.h"
/* b6502 */
+#include "codeopt.h"
#include "codeseg.h"
#include "dataseg.h"
/* Function which is defined and referenced or extern */
PrintFunctionHeader (F, Entry);
MergeCodeLabels (Entry->V.F.CS);
+ RunOpt (Entry->V.F.CS);
fprintf (F, "; Data segment for function %s:\n", Entry->Name);
OutputDataSeg (F, Entry->V.F.DS);
fprintf (F, "; Code segment for function %s:\n", Entry->Name);
/* (C) 1998-2001 llrich von Bassewitz */
/* Wacholderweg 14 */
/* D-70597 Stuttgart */
-/* EMail: uz@musoftware.de */
+/* EMail: uz@cc65.org */
/* */
/* */
/* This software is provided 'as-is', without any expressed or implied */
+unsigned RemoveLabelRef (CodeLabel* L, const struct CodeEntry* E)
+/* Remove a reference to this label, return the number of remaining references */
+{
+ /* Delete the item */
+ CollDeleteItem (&L->JumpFrom, E);
+
+ /* Return the number of remaining references */
+ return CollCount (&L->JumpFrom);
+}
+
+
+
void OutputCodeLabel (FILE* F, const CodeLabel* L)
/* Output the code label to a file */
{
+/*****************************************************************************/
+/* Forwards */
+/*****************************************************************************/
+
+
+
+struct CodeEntry;
+
+
+
/*****************************************************************************/
/* struct CodeLabel */
/*****************************************************************************/
void FreeCodeLabel (CodeLabel* L);
/* Free the given code label */
+unsigned RemoveLabelRef (CodeLabel* L, const struct CodeEntry* E);
+/* Remove a reference to this label, return the number of remaining references */
+
void OutputCodeLabel (FILE* F, const CodeLabel* L);
/* Output the code label to a file */
--- /dev/null
+/*****************************************************************************/
+/* */
+/* codeopt.c */
+/* */
+/* Optimizer subroutines */
+/* */
+/* */
+/* */
+/* (C) 2001 Ullrich von Bassewitz */
+/* Wacholderweg 14 */
+/* D-70597 Stuttgart */
+/* 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. */
+/* */
+/*****************************************************************************/
+
+
+
+/* b6502 */
+#include "codeent.h"
+#include "codeopt.h"
+
+
+
+/*****************************************************************************/
+/* Data */
+/*****************************************************************************/
+
+
+
+/* Counter for the number of changes in one run. The optimizer process is
+ * repeated until there are no more changes.
+ */
+static unsigned OptChanges;
+
+
+
+/*****************************************************************************/
+/* Remove dead jumps */
+/*****************************************************************************/
+
+
+
+static void OptDeadJumps (CodeSeg* S)
+/* Remove dead jumps (jumps to the next instruction) */
+{
+ CodeEntry* E;
+ unsigned I;
+
+ /* Get the number of entries, bail out if we have less than two entries */
+ unsigned Count = CollCount (&S->Entries);
+ if (Count < 2) {
+ return;
+ }
+
+ /* Walk over all entries minus the last one */
+ I = 0;
+ while (I < Count-1) {
+
+ /* Get the next entry */
+ E = CollAt (&S->Entries, I);
+
+ /* Check if it's a branch, if it has a local target, and if the target
+ * is the next instruction.
+ */
+ if (E->AM == AM_BRA) {
+ printf ("BRA on entry %u:\n", I);
+ if (E->JumpTo) {
+ printf (" JumpTo ok\n");
+ if (E->JumpTo->Owner == CollAt (&S->Entries, I+1)) {
+ printf (" Branch to next insn\n");
+ }
+ }
+ }
+
+ if (E->AM == AM_BRA && E->JumpTo && E->JumpTo->Owner == CollAt (&S->Entries, I+1)) {
+
+ /* Remember the label */
+ CodeLabel* L = E->JumpTo;
+
+ /* Jump to next instruction, remove it */
+ unsigned Remaining = RemoveLabelRef (L, E);
+ CollDelete (&S->Entries, I);
+ FreeCodeEntry (E);
+ --Count;
+
+ /* If the label has no more references, remove it */
+ if (Remaining == 0) {
+ CollDeleteItem (&L->Owner->Labels, L);
+ FreeCodeLabel (L);
+ }
+
+ /* Remember we had changes */
+ ++OptChanges;
+
+ } else {
+
+ /* Next entry */
+ ++I;
+
+ }
+ }
+}
+
+
+
+/*****************************************************************************/
+/* Code */
+/*****************************************************************************/
+
+
+
+void RunOpt (CodeSeg* S)
+/* Run the optimizer */
+{
+ printf ("Optimize\n");
+
+ /* Repeat all steps until there are no more changes */
+ do {
+
+ /* Reset the number of changes */
+ OptChanges = 0;
+
+ OptDeadJumps (S);
+
+ } while (OptChanges > 0);
+}
+
+
+
--- /dev/null
+/*****************************************************************************/
+/* */
+/* codeopt.h */
+/* */
+/* Optimizer subroutines */
+/* */
+/* */
+/* */
+/* (C) 2001 Ullrich von Bassewitz */
+/* Wacholderweg 14 */
+/* D-70597 Stuttgart */
+/* 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. */
+/* */
+/*****************************************************************************/
+
+
+
+#ifndef CODEOPT_H
+#define CODEOPT_H
+
+
+
+/* b6502 */
+#include "codeseg.h"
+
+
+
+/*****************************************************************************/
+/* Data */
+/*****************************************************************************/
+
+
+
+/*****************************************************************************/
+/* Code */
+/*****************************************************************************/
+
+
+
+void RunOpt (CodeSeg* S);
+/* Run the optimizer */
+
+
+
+/* End of codeopt.h */
+#endif
+
+
+
}
/* If the instruction is a branch, check for the label and generate it
- * if it does not exist. In case of a PC relative branch (*+x) we will
- * not generate a label, because the target label will not be defined.
+ * if it does not exist. Ignore anything but local labels here.
*/
Label = 0;
- if ((OPC->Info & CI_MASK_BRA) == CI_BRA && Expr[0] != '*') {
+ if ((OPC->Info & CI_MASK_BRA) == CI_BRA && Expr[0] == 'L') {
unsigned Hash;
L->Flags |= LF_DEF;
/* Move it to the code entry */
CollAppend (&E->Labels, L);
+ /* Tell the label about it's owner */
+ L->Owner = E;
}
/* Delete the transfered labels */
/* */
/* */
/* */
-/* (C) 2001 Ullrich von Bassewitz */
-/* Wacholderweg 14 */
-/* D-70597 Stuttgart */
-/* EMail: uz@musoftware.de */
+/* (C) 2001 Ullrich von Bassewitz */
+/* Wacholderweg 14 */
+/* D-70597 Stuttgart */
+/* EMail: uz@cc65.org */
/* */
/* */
/* This software is provided 'as-is', without any expressed or implied */
/* */
/* */
/* */
-/* (C) 2001 Ullrich von Bassewitz */
-/* Wacholderweg 14 */
-/* D-70597 Stuttgart */
-/* EMail: uz@musoftware.de */
+/* (C) 2001 Ullrich von Bassewitz */
+/* Wacholderweg 14 */
+/* D-70597 Stuttgart */
+/* EMail: uz@cc65.org */
/* */
/* */
/* This software is provided 'as-is', without any expressed or implied */
projects / cc65 / commitdiff