default regs, log/trace macros, print mgba-style state

src/crab/cpu.cr

@@ -4,24 +4,28 @@ class CPU
   @pipeline = Deque(Word).new 2
 
   def initialize(@gba : GBA)
+    @r[0] = 0x08000000
+    @r[1] = 0x000000EA
+    @r[13] = 0x03007F00
     @r[15] = 0x08000000
+    @cpsr = 0x6000001F
   end
 
   def fill_pipeline : Nil
     while @pipeline.size < 2
-      puts "Fetch pc: #{hex_str @r[15]}, instr: #{hex_str @gba.bus.read_word @r[15]}, type: #{Instr.from_hash hash_instr @gba.bus.read_word @r[15]}"
+      log "Fetch pc: #{hex_str @r[15]}, instr: #{hex_str @gba.bus.read_word @r[15]}, type: #{Instr.from_hash hash_instr @gba.bus.read_word @r[15]}"
       @pipeline << @gba.bus.read_word @r[15]
       @r[15] &+= 4
     end
   end
 
   def clear_pipeline : Nil
-    puts "Clearing pipeline"
+    log "Clearing pipeline"
     @pipeline.clear
   end
 
   def check_cond(cond : Int) : Bool
-    case 0xF_u8 & cond & 0xF
+    case cond & 0xF
     when 0x0 then bit?(@cpsr, 30)                                        # Z
     when 0x1 then !bit?(@cpsr, 30)                                       # !Z
     when 0x2 then bit?(@cpsr, 29)                                        # C
@@ -44,6 +48,7 @@ class CPU
   def tick : Nil
     fill_pipeline
     instr = @pipeline.shift
+    print_state instr
     execute instr
   end
 
@@ -75,7 +80,7 @@ class CPU
     if check_cond instr >> 28
       hash = hash_instr instr
       instr_type = Instr.from_hash hash
-      puts "Execute #{hex_str instr}: #{instr_type}"
+      log "Execute #{hex_str instr}: #{instr_type}"
       case instr_type
       when Instr::BRANCH
         link = bit?(instr, 24)
@@ -139,4 +144,11 @@ class CPU
       puts "Skipping instruction, cond: #{hex_str instr >> 28}"
     end
   end
+
+  def print_state(instr : Word) : Nil
+    @r.each do |reg|
+      trace "#{hex_str reg, prefix: false} ", newline: false
+    end
+    trace "cpsr: #{hex_str @cpsr, prefix: false} | #{hex_str instr, prefix: false}"
+  end
 end

src/crab/util.cr

@@ -1,5 +1,5 @@
-def hex_str(n : UInt8 | UInt16 | UInt32 | UInt64) : String
-  "0x#{n.to_s(16).rjust(sizeof(typeof(n)) * 2, '0').upcase}"
+def hex_str(n : UInt8 | UInt16 | UInt32 | UInt64, prefix = true) : String
+  (prefix ? "0x" : "") + "#{n.to_s(16).rjust(sizeof(typeof(n)) * 2, '0').upcase}"
 end
 
 macro bit?(value, bit)
@@ -17,3 +17,23 @@ end
 macro clear_bit(value, bit)
   ({{value}} & ~(1 << {{bit}}))
 end
+
+macro trace(value, newline = true)
+  {% if flag? :trace %}
+    {% if newline %}
+      puts {{value}}
+    {% else %}
+      print {{value}}
+    {% end %}
+  {% end %}
+end
+
+macro log(value, newline = true)
+  {% if flag?(:log) %}
+    {% if newline %}
+      puts {{value}}
+    {% else %}
+      print {{value}}
+    {% end %}
+  {% end %}
+end