Fix broken signed right shift

Plus fix broken stack top swap and add stack manipulation keys

Author: drdnar

src/bigint.asm

@@ -672,7 +672,6 @@ BigIntShiftRight:
 	xor	a,a
 bisruiploop:
 	dec	hl
-bisripentry:
 	rr	(hl)
 	djnz	bisruiploop
 	adc	a,a
@@ -688,12 +687,12 @@ _BigIntSignedShiftRight:
 BigIntSignedShiftRight:
 ; Input:
 ;  - HL
+	xor	a,a
 	ld	bc,BIG_INT_SIZE - 1
 	add	hl,bc
 	ld	b,c
 	sra	(hl)
-	xor	a,a
-	jr	bisripentry
+	jr	bisruiploop
 ;-------------------------------------------------------------------------------
 _BigIntShiftBitInOnRight:
 	pop	bc

src/rpnui.c

@@ -197,7 +197,7 @@ bool Rpn_SendKey(sk_key_t k)
         case sk_Ins:
             if (EntryMode == RPN_NO_INPUT)
                 if (BigIntStack_GetSize(MainStack) > 0)
-                    BigIntStack_Push(MainStack, topOfStack);
+                    BigIntStack_Push(MainStack, BigIntStack_Peek(MainStack));
                 else
                     return false;
             else
@@ -209,6 +209,15 @@ bool Rpn_SendKey(sk_key_t k)
         case sk_DecPnt:
             BigIntNot(BigIntStack_Peek(MainStack));
             break;
+        case sk_Comma:
+            BigIntStack_Exchange(MainStack);
+            break;
+        case sk_LParen:
+            BigIntStack_RotateDown(MainStack);
+            break;
+        case sk_RParen:
+            BigIntStack_RotateUp(MainStack);
+            break;
         case sk_Add:
         case sk_Sub:
         case sk_Mul:

src/stack.c

@@ -112,7 +112,7 @@ void BigIntStack_RotateUp(BigIntStack_t* this)
     BigInt_t temp;
     if (this->Size <= 1)
         return;
-    BigIntStack_Pop(this, &temp);
+    BigIntCopyFromTo(this->Stack + this->Size - 1, &temp);
     memmove(this->Stack + 1, this->Stack, (this->Size - 1) * sizeof(BigInt_t));
     BigIntCopyFromTo(&temp, this->Stack);
 }
@@ -138,7 +138,7 @@ void BigIntStack_Exchange(BigIntStack_t* this)
     top = BigIntStack_Peek(this);
     BigIntCopyFromTo(top, &temp);
     BigIntCopyFromTo(top - 1, top);
-    BigIntCopyFromTo(&temp, top);
+    BigIntCopyFromTo(&temp, top - 1);
 }