From 155c200400ac80be1113e35df6637e2f77296d1a Mon Sep 17 00:00:00 2001
From: James Barnett <noreply@jamesbarnett.xyz>
Date: Fri, 22 Jun 2018 19:51:31 +0100
Subject: Add first few 16-Bit Load ops

---
 src/main/kotlin/cpu/Registers.kt          |  7 ++++++
 src/main/kotlin/cpu/opcodes/Loads16Bit.kt | 40 +++++++++++++++++++++++++++++++
 2 files changed, 47 insertions(+)
 create mode 100644 src/main/kotlin/cpu/opcodes/Loads16Bit.kt

(limited to 'src')

diff --git a/src/main/kotlin/cpu/Registers.kt b/src/main/kotlin/cpu/Registers.kt
index 6d1e626..5f45e87 100644
--- a/src/main/kotlin/cpu/Registers.kt
+++ b/src/main/kotlin/cpu/Registers.kt
@@ -115,5 +115,12 @@ class Registers {
     return currentHL
   }
 
+  fun decrementAndGetSP(): Int {
+    return if(SP > 0x0000) {
+      --SP
+    } else {
+      SP
+    }
+  }
 
 }
\ No newline at end of file
diff --git a/src/main/kotlin/cpu/opcodes/Loads16Bit.kt b/src/main/kotlin/cpu/opcodes/Loads16Bit.kt
new file mode 100644
index 0000000..6c915cf
--- /dev/null
+++ b/src/main/kotlin/cpu/opcodes/Loads16Bit.kt
@@ -0,0 +1,40 @@
+package cpu.opcodes
+
+import cpu.Operation
+import BitManipulation as bm
+
+// 8-Bit Loads
+var loads16Bit = mapOf(
+
+  0x01 to Operation("LD BC,nn", 2, 12, {r, _, a -> r.BC = bm.argsToWord(a)}),
+  0x11 to Operation("LD DE,nn", 2, 12, {r, _, a -> r.DE = bm.argsToWord(a)}),
+  0x21 to Operation("LD HL,nn", 2, 12, {r, _, a -> r.HL = bm.argsToWord(a)}),
+  0x31 to Operation("LD SP,nn", 2, 12, {r, _, a -> r.SP = bm.argsToWord(a)}),
+
+  0xF9 to Operation("LD SP,HL", 0, 8, {r, _, _ -> r.SP = r.HL}),
+
+  0xF8 to Operation("LDHL SP,n", 1, 12, {r, _, a -> r.HL = (r.SP + a[0])}), // TODO - not sure what the flags should be here
+  0x08 to Operation("LD (nn),SP", 2, 20, {r, m, a ->
+    m.writeByte(bm.argsToWord(a), bm.getLsb(r.SP))
+    m.writeByte(bm.argsToWord(a) + 1, bm.getMsb(r.SP))
+    // TODO - not sure if the lsb/msb order is right here
+  }),
+
+  0xF5 to Operation("PUSH AF", 0, 16, {r, m, _ ->
+    m.writeByte(r.decrementAndGetSP(), bm.getMsb(r.AF))
+    m.writeByte(r.decrementAndGetSP(), bm.getLsb(r.AF))
+  }),
+  0xC5 to Operation("PUSH BC", 0, 16, {r, m, _ ->
+    m.writeByte(r.decrementAndGetSP(), bm.getMsb(r.BC))
+    m.writeByte(r.decrementAndGetSP(), bm.getLsb(r.BC))
+  }),
+  0xD5 to Operation("PUSH DE", 0, 16, {r, m, _ ->
+    m.writeByte(r.decrementAndGetSP(), bm.getMsb(r.DE))
+    m.writeByte(r.decrementAndGetSP(), bm.getLsb(r.DE))
+  }),
+  0xE5 to Operation("PUSH HL", 0, 16, {r, m, _ ->
+    m.writeByte(r.decrementAndGetSP(), bm.getMsb(r.HL))
+    m.writeByte(r.decrementAndGetSP(), bm.getLsb(r.HL))
+  })
+
+)
-- 
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