next round of fixes: JR, JP, RR Flags, decode SRL

AnnsAnns · Jun 2, 2024 · faa4b65 · faa4b65
1 parent 117479e
commit faa4b65
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Showing 5 changed files with 23 additions and 8 deletions.
diff --git a/src/cpu/decode.rs b/src/cpu/decode.rs
@@ -215,7 +215,7 @@ impl CPU {
             0x3 => match tail {
                 0x0 => Instructions::JR(
                     InstParam::ConditionCodes(InstructionCondition::NotCarry),
-                    InstParam::Number8Bit(self.get_8bit_from_pc()),
+                    InstParam::SignedNumber8Bit(self.get_8bit_from_pc() as i8),
                 ),
                 0x1 => self.decode_0x0_to_0x3_commons(opcode)?,
                 0x2 => Instructions::LDHLDA,
@@ -442,7 +442,11 @@ impl CPU {
             0x0 => Instructions::RLC(register),
             0x1 => Instructions::RL(register),
             0x2 => Instructions::SLA(register),
-            0x3 => Instructions::SWAP(register),
+            0x3 => match tail {
+                0x0..=0x7 => Instructions::SWAP(register),
+                0x8..=0xF => Instructions::SRL(register),
+                _ => return self.not_implemented(opcode),
+            }
             0x4 => Instructions::BIT(InstParam::Unsigned3Bit(0 + offset), register),
             0x5 => Instructions::BIT(InstParam::Unsigned3Bit(2 + offset), register),
             0x6 => Instructions::BIT(InstParam::Unsigned3Bit(4 + offset), register),

diff --git a/src/cpu/instructions/bit_shift/rr.rs b/src/cpu/instructions/bit_shift/rr.rs
@@ -24,10 +24,10 @@ impl CPU {
         let result = (value >> 1) | shift_into_result;
         (
             ConditionCodes {
-                zero: if result != 0 && set_zero {
-                    FlagState::Unset
-                } else {
+                zero: if set_zero && result == 0 {
                     FlagState::Set
+                } else {
+                    FlagState::Unset
                 },
                 subtract: FlagState::Unset,
                 half_carry: FlagState::Unset,

diff --git a/src/cpu/instructions/jumps_subroutines.rs b/src/cpu/instructions/jumps_subroutines.rs
@@ -44,6 +44,11 @@ impl CPU {
     pub fn jp_cc_n16(&mut self, cc:bool, target: u16) -> InstructionResult {
         if cc {
             self.set_16bit_register(Register16Bit::PC, target);
+        } else {
+            // 3 bytes for the jp instruction
+            // Even if the condition is false, the instruction is still 3 bytes
+            // So we need to increment the PC by 3
+            self.set_16bit_register(Register16Bit::PC, self.get_16bit_register(Register16Bit::PC)+3);
         }
 
 
@@ -127,6 +132,11 @@ impl CPU {
         pub fn ret_cc(&mut self, cc: bool) -> InstructionResult {
             if cc {
                 self.pop_r16(Register16Bit::PC);
+            } else {
+                // 1 bytes for the ret instruction
+                // Even if the condition is false, the instruction is still 1 bytes
+                // So we need to increment the PC by 1
+                self.set_16bit_register(Register16Bit::PC, self.get_16bit_register(Register16Bit::PC)+1);
             }
 
             InstructionResult {

diff --git a/src/cpu/step.rs b/src/cpu/step.rs
@@ -436,7 +436,7 @@ impl CPU {
                     InstParam::SignedNumber8Bit(target_addr) => {
                         self.jr_cc_n16(self.check_condition(cond), *target_addr)
                     }
-                    _ => return Err(format!("CALL of {:?} not implemented", optional_target)),
+                    _ => return Err(format!("JR of {:?} not implemented", optional_target)),
                 },
                 _ => return Err(format!("CALL of {:?} not implemented", target_or_condition)),
             },

diff --git a/src/main.rs b/src/main.rs
@@ -31,10 +31,11 @@ const DOTS_PER_LINE: u32 = 456;
 const TIME_PER_FRAME: f32 = 1.0 / 60.0 * 1000.0;
 
 const DUMP_GAMEBOY_DOCTOR_LOG: bool = true;
+const WINDOWS: bool = true;
 
 #[macroquad::main("GB Emulator")]
 async fn main() {
-    // Set up logging
+    //Set up logging
     let config = LogConfigBuilder::builder()
     .size(1 * 100)
     .roll_count(10)
@@ -218,7 +219,7 @@ async fn main() {
                 frame += 1;
 
                 // Dump memory every 3 seconds
-                if dump_time.elapsed().as_secs() >= 3 {
+                if !WINDOWS && dump_time.elapsed().as_secs() >= 3 {
                     dump_time = time::Instant::now();
                     cpu.dump_memory();
                 }