From 7001db8c905c3747e55a0c327a5cb69ca8ecd29d Mon Sep 17 00:00:00 2001
From: Matthew Berry <me@mattrb.com>
Date: Sun, 21 Aug 2022 15:47:11 -0700
Subject: [PATCH] update mmio from chained conditionals to case statement

---
 src/crab/gba/keypad.cr | 48 ++++++------------------------------------
 src/crab/gba/mmio.cr   | 33 ++++++++++++-----------------
 src/crab/gba/reg.cr    | 35 ++++++++++++++++++++++++++++++
 3 files changed, 54 insertions(+), 62 deletions(-)

diff --git a/src/crab/gba/keypad.cr b/src/crab/gba/keypad.cr
index b2ef53d..a7f63a6 100644
--- a/src/crab/gba/keypad.cr
+++ b/src/crab/gba/keypad.cr
@@ -1,57 +1,21 @@
 module GBA
   class Keypad
-    class KEYINPUT < BitField(UInt16)
-      num not_used, 6
-      bool l
-      bool r
-      bool down
-      bool up
-      bool left
-      bool right
-      bool start
-      bool :select
-      bool b
-      bool a
-    end
-
-    class KEYCNT < BitField(UInt16)
-      bool irq_condition
-      bool irq_enable
-      num not_used, 4
-      bool l
-      bool r
-      bool down
-      bool up
-      bool left
-      bool right
-      bool start
-      bool :select
-      bool b
-      bool a
-    end
-
-    @keyinput = KEYINPUT.new 0xFFFF_u16
-    @keycnt = KEYCNT.new 0xFFFF_u16
+    @keyinput = Reg::KEYINPUT.new 0xFFFF_u16
+    @keycnt = Reg::KEYCNT.new 0xFFFF_u16
 
     def initialize(@gba : GBA)
     end
 
     def [](io_addr : Int) : Byte
       case io_addr
-      when 0x130 then 0xFF_u8 & @keyinput.value
-      when 0x131 then 0xFF_u8 & @keyinput.value >> 8
-      when 0x132 then 0xFF_u8 & @keycnt.value
-      when 0x133 then 0xFF_u8 & @keycnt.value >> 8
-      else            raise "Unimplemented keypad read ~ addr:#{hex_str io_addr.to_u8!}"
+      when 0x130..0x131 then @keyinput.read_byte(io_addr & 1)
+      when 0x132..0x133 then @keycnt.read_byte(io_addr & 1)
+      else                   abort "Unreachable keypad read #{hex_str io_addr}"
       end
     end
 
     def []=(io_addr : Int, value : Byte) : Nil
-      case io_addr
-      when 0x130 then nil
-      when 0x131 then nil
-      else            raise "Unimplemented keypad write ~ addr:#{hex_str io_addr.to_u8!}, val:#{value}"
-      end
+      puts "TODO: Implement stopping and keycnt behavior" if 0x132 <= io_addr <= 0x133
     end
 
     def handle_input(input : Input, pressed : Bool) : Nil
diff --git a/src/crab/gba/mmio.cr b/src/crab/gba/mmio.cr
index bca5b15..b4fbf64 100644
--- a/src/crab/gba/mmio.cr
+++ b/src/crab/gba/mmio.cr
@@ -12,8 +12,7 @@ module GBA
       when 0x060..0x0A7 then @gba.apu[io_addr]
       when 0x0B0..0x0DF then @gba.dma[io_addr]
       when 0x100..0x10F then @gba.timer[io_addr]
-      when 0x120..0x12B, 0x134..0x159
-        # todo: serial
+      when 0x120..0x12B, 0x134..0x159 # todo: serial
         if io_addr == 0x135
           0x80_u8
         else
@@ -29,25 +28,19 @@ module GBA
 
     def []=(index : Int, value : Byte) : Nil
       io_addr = 0xFFFFFF_u32 & index
-      if io_addr <= 0x05F
-        @gba.ppu[io_addr] = value
-      elsif io_addr <= 0xAF
-        @gba.apu[io_addr] = value
-      elsif io_addr <= 0xFF
-        @gba.dma[io_addr] = value
-      elsif 0x100 <= io_addr <= 0x10F
-        @gba.timer[io_addr] = value
-      elsif 0x130 <= io_addr <= 0x133
-        @gba.keypad[io_addr]
-      elsif 0x120 <= io_addr <= 0x12F || 0x134 <= io_addr <= 0x1FF
-        # todo: serial
-      elsif 0x200 <= io_addr <= 0x203 || 0x208 <= io_addr <= 0x209
-        @gba.interrupts[io_addr] = value
-      elsif 0x204 <= io_addr <= 0x205
-        @waitcnt.write_byte(io_addr & 1, value)
-      elsif io_addr == 0x301
+      case io_addr
+      when 0x000..0x055 then @gba.ppu[io_addr] = value
+      when 0x060..0x0A7 then @gba.apu[io_addr] = value
+      when 0x0B0..0x0DF then @gba.dma[io_addr] = value
+      when 0x100..0x10F then @gba.timer[io_addr] = value
+      when 0x120..0x12B, 0x134..0x159 # todo: serial
+      when 0x130..0x133 then @gba.keypad[io_addr] = value
+      when 0x200..0x203,
+           0x208..0x209 then @gba.interrupts[io_addr] = value
+      when 0x204..0x205 then @waitcnt.write_byte(io_addr & 1, value)
+      when 0x301
         if bit?(value, 7)
-          abort "Stopping not supported"
+          puts "TODO: Implement stopping behavior"
         else
           @gba.cpu.halted = true
         end
diff --git a/src/crab/gba/reg.cr b/src/crab/gba/reg.cr
index ee3cd8f..a40d318 100644
--- a/src/crab/gba/reg.cr
+++ b/src/crab/gba/reg.cr
@@ -286,5 +286,40 @@ module GBA
       num not_used, 11, read_only: true
       num evy_coefficient, 5
     end
+
+    ####################
+    # Keypad
+
+    class KEYINPUT < BitField(UInt16)
+      include Base16
+      num not_used, 6
+      bool l
+      bool r
+      bool down
+      bool up
+      bool left
+      bool right
+      bool start
+      bool :select
+      bool b
+      bool a
+    end
+
+    class KEYCNT < BitField(UInt16)
+      include Base16
+      bool irq_condition
+      bool irq_enable
+      num not_used, 4
+      bool l
+      bool r
+      bool down
+      bool up
+      bool left
+      bool right
+      bool start
+      bool :select
+      bool b
+      bool a
+    end
   end
 end