Extend OPtShift3 to shift counts larger than 1.

git-svn-id: svn://svn.cc65.org/cc65/trunk@5713 b7a2c559-68d2-44c3-8de9-860c34a00d81

diff --git a/src/cc65/codeopt.c b/src/cc65/codeopt.c
index 51dbfcec2d485457cfd762e7aa72fdf0729f3819..18444a26544befe29758f3cd4793e862d1ba169b 100644 (file)
--- a/src/cc65/codeopt.c
+++ b/src/cc65/codeopt.c
@@ -261,7 +261,11 @@ static unsigned OptShift3 (CodeSeg* S)
  *
  *      ror     a
  *
- * if X is zero on entry and unused later.
+ * if X is zero on entry and unused later. For shift counts > 1, more
+ *
+ *      shr     a
+ *
+ * must be added.
  */
 {
     unsigned Changes = 0;
@@ -287,12 +291,21 @@ static unsigned OptShift3 (CodeSeg* S)
            L[1]->OPC == OP65_INX                               &&
            L[0]->JumpTo->Owner == L[2]                         &&
            !CS_RangeHasLabel (S, I, 2)                         &&
-            CE_IsCallTo (L[2], "shrax1")                        &&
+            L[2]->OPC == OP65_JSR                               &&
+            strlen (L[2]->Arg) == 6                             &&
+            memcmp (L[2]->Arg, "shrax", 5) == 0                 &&
+            IsDigit (L[2]->Arg[5])                              &&
            !RegXUsed (S, I+3)) {
 
+            unsigned ShiftCount = (L[2]->Arg[5] - '0');
+
             /* Add the replacement insn instead */
             CodeEntry* X = NewCodeEntry (OP65_ROR, AM65_ACC, "a", 0, L[2]->LI);
             CS_InsertEntry (S, X, I+3);
+            while (--ShiftCount) {
+                X = NewCodeEntry (OP65_LSR, AM65_ACC, "a", 0, L[2]->LI);
+                CS_InsertEntry (S, X, I+4);
+            }
 
            /* Remove the bcs/dex/jsr */
            CS_DelEntries (S, I, 3);