Write FM feedback to YM2612. Overwrites Algorithm!

rhargreaves · Nov 16, 2018 · e47e44d · e47e44d
1 parent d8f68a5
commit e47e44d
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Showing 3 changed files with 19 additions and 1 deletion.
diff --git a/src/synth.c b/src/synth.c
@@ -85,7 +85,9 @@ void synth_algorithm(u8 channel, u8 algorithm)
     synth_writeFm(channel, 0xB0, algorithm);
 }
 
-void synth_feedback(u8 channel, u8 feedback) {
+void synth_feedback(u8 channel, u8 feedback)
+{
+    synth_writeFm(channel, 0xB0, feedback << 3);
 }
 
 void synth_operatorTotalLevel(u8 channel, u8 op, u8 totalLevel)

diff --git a/tests/test_main.c b/tests/test_main.c
@@ -47,6 +47,7 @@ int main(void)
         cmocka_unit_test(test_synth_sets_total_level_reg_chan),
         cmocka_unit_test(test_synth_sets_stereo_reg_chan),
         cmocka_unit_test(test_synth_sets_algorithm),
+        cmocka_unit_test(test_synth_sets_feedback),
         cmocka_unit_test(test_synth_sets_operator_total_level),
 
         cmocka_unit_test(test_psg_chip_sets_note_on_psg),

diff --git a/tests/test_synth.c b/tests/test_synth.c
@@ -12,6 +12,7 @@ extern void __real_synth_pitch(u8 channel, u8 octave, u16 freqNumber);
 extern void __real_synth_totalLevel(u8 channel, u8 totalLevel);
 extern void __real_synth_stereo(u8 channel, u8 stereo);
 extern void __real_synth_algorithm(u8 channel, u8 algorithm);
+extern void __real_synth_feedback(u8 channel, u8 feedback);
 extern void __real_synth_operatorTotalLevel(u8 channel, u8 op, u8 totalLevel);
 
 static void test_synth_init_sets_initial_registers(void** state)
@@ -126,6 +127,20 @@ static void test_synth_sets_algorithm(void** state)
     }
 }
 
+static void test_synth_sets_feedback(void** state)
+{
+    u8 feedback = 1;
+    for (u8 chan = 0; chan < 6; chan++) {
+        u8 regOffset = chan % 3;
+        u8 regPart = chan < 3 ? 0 : 1;
+        expect_value(__wrap_YM2612_writeReg, part, regPart);
+        expect_value(__wrap_YM2612_writeReg, reg, 0xB0 + regOffset);
+        expect_value(__wrap_YM2612_writeReg, data, feedback << 3);
+
+        __real_synth_feedback(chan, feedback);
+    }
+}
+
 static void test_synth_sets_operator_total_level(void** state)
 {
     u8 totalLevel = 50;