Implement RRA (ROR + ADC) (absolute, X).

hainesr · Oct 31, 2020 · 0eacf06 · 0eacf06
1 parent 5bd792f
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diff --git a/lib/mos6502/cpu_illegal_instructions.rb b/lib/mos6502/cpu_illegal_instructions.rb
@@ -219,6 +219,11 @@ def illegal_instructions
           absolute(@x)
         },
 
+        # RRA (ROR + ADC) (absolute, X)
+        0x7f => lambda {
+          rra(absolute(@x))
+        },
+
         # NOP (immediate)
         0x80 => lambda {
           next_byte

diff --git a/test/cpu_illegal_acc_ops_test.rb b/test/cpu_illegal_acc_ops_test.rb
@@ -90,6 +90,7 @@ def test_absolute_x
       [0x1f, 0xbb, 0x98, true, false, true, false],   # SLO
       [0x3f, 0x10, 0x98, false, false, true, false],  # RLA
       [0x5f, 0x55, 0x66, false, false, false, false], # SRE
+      [0x7f, 0x99, 0x66, true, false, false, true],   # RRA
       [0xdf, 0x33, 0xcb, false, false, false, false], # DCP
       [0xff, 0x65, 0xcd, false, false, false, false]  # ISC
     ].each do |opcode, a, mem, negative, zero, carry, overflow|