Add CALLs

2 files changed, 29 insertions, 0 deletions

diff --git a/src/main/kotlin/cpu/Cpu.kt b/src/main/kotlin/cpu/Cpu.kt
index ce5ba43..3336900 100644
--- a/src/main/kotlin/cpu/Cpu.kt
+++ b/src/main/kotlin/cpu/Cpu.kt
@@ -19,6 +19,7 @@ class Cpu {
     stdCommandGroup.putAll(misc)
     stdCommandGroup.putAll(rotates)
     stdCommandGroup.putAll(jumps)
+    stdCommandGroup.putAll(calls)
     standardOpcodes = stdCommandGroup.toMap()
 
     val extCommandGroup: MutableMap<Int, Operation> = mutableMapOf()
diff --git a/src/main/kotlin/cpu/opcodes/Calls.kt b/src/main/kotlin/cpu/opcodes/Calls.kt
new file mode 100644
index 0000000..697b56c
--- /dev/null
+++ b/src/main/kotlin/cpu/opcodes/Calls.kt
@@ -0,0 +1,28 @@
+package cpu.opcodes
+
+import cpu.Operation
+import cpu.Registers
+import cpu.Registers.Flag
+import ram.Ram
+import BitManipulation as bm
+
+val calls = mapOf(
+
+  0xCD to Operation("CALL nn", 2, 12, {r, m, a -> call(bm.argsToWord(a), r, m)}),
+
+  0xC4 to Operation("CALL NZ,nn", 2, 12, {r, m, a -> if(r.getFlag(Flag.ZERO) == 0) call(bm.argsToWord(a), r, m)}),
+  0xCC to Operation("CALL Z,nn", 2, 12, {r, m, a -> if(r.getFlag(Flag.ZERO) == 1) call(bm.argsToWord(a), r, m)}),
+  0xD4 to Operation("CALL NC,nn", 2, 12, {r, m, a -> if(r.getFlag(Flag.CARRY) == 0) call(bm.argsToWord(a), r, m)}),
+  0xDC to Operation("CALL C,nn", 2, 12, {r, m, a -> if(r.getFlag(Flag.CARRY) == 1) call(bm.argsToWord(a), r, m)})
+
+)
+
+private fun call(word: Int, r: Registers, m: Ram) {
+
+  val nextAddress = (r.PC + 3) and 0xFFFF
+
+  m.writeByte(r.decrementAndGetSP(), bm.getMsb(nextAddress))
+  m.writeByte(r.decrementAndGetSP(), bm.getLsb(nextAddress))
+
+  r.PC = word
+}
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