Cleanup, more 65c02 code

git-svn-id: svn://svn.cc65.org/cc65/trunk@1063 b7a2c559-68d2-44c3-8de9-860c34a00d81

diff --git a/src/cc65/coptind.c b/src/cc65/coptind.c
index ec9d0df1a9146b8036f6ef7b0bfdf377ece9b22b..982c744d4b0c42f3144abc71dbe671db8fc2521a 100644 (file)
--- a/src/cc65/coptind.c
+++ b/src/cc65/coptind.c
@@ -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 */