From 22f3463e3128947df69cb6444c82bd73350d5cc5 Mon Sep 17 00:00:00 2001
From: James Barnett <noreply@jamesbarnett.xyz>
Date: Thu, 14 Jun 2018 21:28:31 +0100
Subject: Move bit manipulation helpers out into their own object

---
 src/main/kotlin/BitManipulation.kt | 27 +++++++++++++
 src/main/kotlin/cpu/Registers.kt   | 77 ++++++++++++++------------------------
 2 files changed, 55 insertions(+), 49 deletions(-)
 create mode 100644 src/main/kotlin/BitManipulation.kt

(limited to 'src')

diff --git a/src/main/kotlin/BitManipulation.kt b/src/main/kotlin/BitManipulation.kt
new file mode 100644
index 0000000..a9f9493
--- /dev/null
+++ b/src/main/kotlin/BitManipulation.kt
@@ -0,0 +1,27 @@
+object BitManipulation {
+
+  fun bytesToWord(msb: Int, lsb: Int): Int {
+    return msb.shl(8) + lsb
+  }
+
+  fun getMsb(value: Int): Int {
+    return value.shr(8)
+  }
+
+  fun getLsb(value: Int): Int {
+    return value.and(0xFF)
+  }
+
+  fun validateUnsigned8Bit(value: Int) {
+    if(value < 0 || value > 255) {
+      throw IllegalArgumentException("Value $value is not an unsigned 8-Bit value")
+    }
+  }
+
+  fun validateUnsigned16Bit(value: Int) {
+    if(value < 0 || value > 65535) {
+      throw IllegalArgumentException("Value $value is not an unsigned 16-Bit value")
+    }
+  }
+
+}
\ No newline at end of file
diff --git a/src/main/kotlin/cpu/Registers.kt b/src/main/kotlin/cpu/Registers.kt
index 6cf417e..7aa144f 100644
--- a/src/main/kotlin/cpu/Registers.kt
+++ b/src/main/kotlin/cpu/Registers.kt
@@ -1,124 +1,103 @@
 package cpu
 
+import BitManipulation as bm
+
 class Registers {
 
   // General purpose registers
   var B: Int = 0
     set(value) {
-      validateUnsigned8Bit(value)
+      bm.validateUnsigned8Bit(value)
       field = value
     }
   var C: Int = 0
     set(value) {
-      validateUnsigned8Bit(value)
+      bm.validateUnsigned8Bit(value)
       field = value
     }
   var D: Int = 0
     set(value) {
-      validateUnsigned8Bit(value)
+      bm.validateUnsigned8Bit(value)
       field = value
     }
   var E: Int = 0
     set(value) {
-      validateUnsigned8Bit(value)
+      bm.validateUnsigned8Bit(value)
       field = value
     }
   var H: Int = 0
     set(value) {
-      validateUnsigned8Bit(value)
+      bm.validateUnsigned8Bit(value)
       field = value
     }
   var L: Int = 0
     set(value) {
-      validateUnsigned8Bit(value)
+      bm.validateUnsigned8Bit(value)
       field = value
     }
 
   // Special registers
   var A: Int = 0
     set(value) {
-      validateUnsigned8Bit(value)
+      bm.validateUnsigned8Bit(value)
       field = value
     }
   var F: Int = 0
     set(value) {
-      validateUnsigned8Bit(value)
+      bm.validateUnsigned8Bit(value)
       field = value
     }
   var SP: Int = 0
     set(value) {
-      validateUnsigned16Bit(value)
+      bm.validateUnsigned16Bit(value)
       field = value
     }
   var PC: Int = 0
     set(value) {
-      validateUnsigned16Bit(value)
+      bm.validateUnsigned16Bit(value)
       field = value
     }
 
   // 16-Bit accessors
   var AF: Int
     get() {
-      return bytesToWord(A, F)
+      return bm.bytesToWord(A, F)
     }
     set(value) {
-      validateUnsigned16Bit(value)
-      A = getMsb(value)
-      F = getLsb(value)
+      bm.validateUnsigned16Bit(value)
+      A = bm.getMsb(value)
+      F = bm.getLsb(value)
     }
 
   var BC: Int
     get() {
-      return bytesToWord(B, C)
+      return bm.bytesToWord(B, C)
     }
     set(value) {
-      validateUnsigned16Bit(value)
-      B = getMsb(value)
-      C = getLsb(value)
+      bm.validateUnsigned16Bit(value)
+      B = bm.getMsb(value)
+      C = bm.getLsb(value)
     }
 
   var DE: Int
     get() {
-      return bytesToWord(D, E)
+      return bm.bytesToWord(D, E)
     }
     set(value) {
-      validateUnsigned16Bit(value)
-      D = getMsb(value)
-      E = getLsb(value)
+      bm.validateUnsigned16Bit(value)
+      D = bm.getMsb(value)
+      E = bm.getLsb(value)
     }
 
   var HL: Int
     get() {
-      return bytesToWord(H, L)
+      return bm.bytesToWord(H, L)
     }
     set(value) {
-      validateUnsigned16Bit(value)
-      H = getMsb(value)
-      L = getLsb(value)
+      bm.validateUnsigned16Bit(value)
+      H = bm.getMsb(value)
+      L = bm.getLsb(value)
     }
 
-  private fun bytesToWord(msb: Int, lsb: Int): Int {
-    return msb.shl(8) + lsb
-  }
-
-  private fun getMsb(value: Int): Int {
-    return value.shr(8)
-  }
-
-  private fun getLsb(value: Int): Int {
-    return value.and(0xFF)
-  }
-
-  private fun validateUnsigned8Bit(value: Int) {
-    if(value < 0 || value > 255) {
-      throw IllegalArgumentException("Value $value is not an unsigned 8-Bit value")
-    }
-  }
-
-  private fun validateUnsigned16Bit(value: Int) {
-    if(value < 0 || value > 65535) {
-      throw IllegalArgumentException("Value $value is not an unsigned 16-Bit value")
-    }
-  }
 
 }
\ No newline at end of file
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