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Cleanup, more 65c02 code

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git-svn-id: svn://svn.cc65.org/cc65/trunk@1063 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
cuz 2001-10-18 20:45:24 +00:00
parent b4393c9ac6
commit c4627941e8
1 changed files with 72 additions and 79 deletions
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151
src/cc65/coptind.c
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@ -37,11 +37,58 @@
#include "codeent.h"
#include "codeinfo.h"
#include "codeopt.h"
#include "cpu.h"
#include "error.h"
#include "coptind.h"
/*****************************************************************************/
/* Helper functions */
/*****************************************************************************/
static int GetBranchDist (CodeSeg* S, unsigned From, CodeEntry* To)
/* Get the branch distance between the two entries and return it. The distance
* will be negative for backward jumps and positive for forward jumps.
*/
{
/* Get the index of the branch target */
unsigned TI = CS_GetEntryIndex (S, To);
/* Determine the branch distance */
int Distance = 0;
if (TI >= From) {
/* Forward branch, do not count the current insn */
unsigned J = From+1;
while (J < TI) {
CodeEntry* N = CS_GetEntry (S, J++);
Distance += N->Size;
}
} else {
/* Backward branch */
unsigned J = TI;
while (J < From) {
CodeEntry* N = CS_GetEntry (S, J++);
Distance -= N->Size;
}
}
/* Return the calculated distance */
return Distance;
}
static int IsShortDist (int Distance)
/* Return true if the given distance is a short branch distance */
{
return (Distance >= -125 && Distance <= 125);
}
/*****************************************************************************/
/* Replace jumps to RTS by RTS */
/*****************************************************************************/
@ -156,21 +203,13 @@ unsigned OptDeadJumps (CodeSeg* S)
/* Remove dead jumps (jumps to the next instruction) */
{
unsigned Changes = 0;
CodeEntry* E;
unsigned I;
/* Get the number of entries, bail out if we have less than two entries */
unsigned Count = CS_GetEntryCount (S);
if (Count < 2) {
return 0;
}
/* Walk over all entries minus the last one */
I = 0;
while (I < Count-1) {
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
/* Get the next entry */
E = CS_GetEntry (S, I);
CodeEntry* E = CS_GetEntry (S, I);
/* Check if it's a branch, if it has a local target, and if the target
* is the next instruction.
@ -180,9 +219,6 @@ unsigned OptDeadJumps (CodeSeg* S)
/* Delete the dead jump */
CS_DelEntry (S, I);
/* Keep the number of entries updated */
--Count;
/* Remember, we had changes */
++Changes;
@ -212,17 +248,10 @@ unsigned OptDeadCode (CodeSeg* S)
*/
{
unsigned Changes = 0;
unsigned I;
/* Get the number of entries, bail out if we have less than two entries */
unsigned Count = CS_GetEntryCount (S);
if (Count < 2) {
return 0;
}
/* Walk over all entries */
I = 0;
while (I < Count) {
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* N;
@ -239,9 +268,6 @@ unsigned OptDeadCode (CodeSeg* S)
/* Delete the next entry */
CS_DelEntry (S, I+1);
/* Keep the number of entries updated */
--Count;
/* Remember, we had changes */
++Changes;
@ -389,17 +415,10 @@ unsigned OptRTS (CodeSeg* S)
*/
{
unsigned Changes = 0;
unsigned I;
/* Get the number of entries, bail out if we have less than 2 entries */
unsigned Count = CS_GetEntryCount (S);
if (Count < 2) {
return 0;
}
/* Walk over all entries minus the last one */
I = 0;
while (I < Count-1) {
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* N;
@ -451,17 +470,10 @@ unsigned OptJumpTarget (CodeSeg* S)
CodeEntry* T2; /* Jump target entry 2 */
CodeLabel* TL1; /* Target label 1 */
unsigned TI; /* Target index */
unsigned I;
/* Get the number of entries, bail out if we have not enough */
unsigned Count = CS_GetEntryCount (S);
if (Count < 3) {
return 0;
}
/* Walk over the entries */
I = 0;
while (I < Count-1) {
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
/* Get next entry */
E2 = CS_GetEntry (S, I+1);
@ -507,7 +519,6 @@ unsigned OptJumpTarget (CodeSeg* S)
/* Remove the entry preceeding the jump */
CS_DelEntry (S, I);
--Count;
/* Remember, we had changes */
++Changes;
@ -546,17 +557,10 @@ unsigned OptCondBranches (CodeSeg* S)
*/
{
unsigned Changes = 0;
unsigned I;
/* Get the number of entries, bail out if we have not enough */
unsigned Count = CS_GetEntryCount (S);
if (Count < 2) {
return 0;
}
/* Walk over the entries */
I = 0;
while (I < Count-1) {
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* N;
CodeLabel* L;
@ -583,7 +587,6 @@ unsigned OptCondBranches (CodeSeg* S)
/* Remove the conditional branch */
CS_DelEntry (S, I+1);
--Count;
/* Remember, we had changes */
++Changes;
@ -616,7 +619,6 @@ unsigned OptCondBranches (CodeSeg* S)
/* Remove the conditional branch */
CS_DelEntry (S, I);
--Count;
/* Remember, we had changes */
++Changes;
@ -1090,38 +1092,20 @@ unsigned OptBranchDist (CodeSeg* S)
CodeEntry* E = CS_GetEntry (S, I);
/* Check if it's a conditional branch to a local label. */
if ((E->Info & OF_CBRA) != 0) {
if (E->Info & OF_CBRA) {
/* Is this a branch to a local symbol? */
if (E->JumpTo != 0) {
/* Get the index of the branch target */
unsigned TI = CS_GetEntryIndex (S, E->JumpTo->Owner);
/* Determine the branch distance */
int Distance = 0;
if (TI >= I) {
/* Forward branch */
unsigned J = I;
while (J < TI) {
CodeEntry* N = CS_GetEntry (S, J++);
Distance += N->Size;
}
} else {
/* Backward branch */
unsigned J = TI;
while (J < I) {
CodeEntry* N = CS_GetEntry (S, J++);
Distance += N->Size;
}
}
/* Check if the branch distance is short */
int IsShort = IsShortDist (GetBranchDist (S, I, E->JumpTo->Owner));
/* Make the branch short/long according to distance */
if ((E->Info & OF_LBRA) == 0 && Distance > 125) {
if ((E->Info & OF_LBRA) == 0 && !IsShort) {
/* Short branch but long distance */
CE_ReplaceOPC (E, MakeLongBranch (E->OPC));
++Changes;
} else if ((E->Info & OF_LBRA) != 0 && Distance < 125) {
} else if ((E->Info & OF_LBRA) != 0 && IsShort) {
/* Long branch but short distance */
CE_ReplaceOPC (E, MakeShortBranch (E->OPC));
++Changes;
@ -1134,6 +1118,15 @@ unsigned OptBranchDist (CodeSeg* S)
++Changes;
}
} else if (CPU == CPU_65C02 &&
(E->Info & OF_UBRA) != 0 &&
E->JumpTo != 0 &&
IsShortDist (GetBranchDist (S, I, E->JumpTo->Owner))) {
/* The jump is short and may be replaced by a BRA on the 65C02 CPU */
CE_ReplaceOPC (E, OP65_BRA);
++Changes;
}
/* Next entry */