SPC700: implement BRA and flag-conditional branch instructions

twvd · Nov 23, 2023 · ede7064 · ede7064
1 parent a51e648
commit ede7064
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Showing 2 changed files with 37 additions and 9 deletions.
diff --git a/src/snes/cpu_spc700/cpu.rs b/src/snes/cpu_spc700/cpu.rs
@@ -254,6 +254,15 @@ where
             InstructionType::TCALL => self.op_tcall(instr),
             InstructionType::BBC => self.op_bbx(instr, false),
             InstructionType::BBS => self.op_bbx(instr, true),
+            InstructionType::BCC => self.op_branch(instr, !self.regs.test_flag(Flag::C)),
+            InstructionType::BCS => self.op_branch(instr, self.regs.test_flag(Flag::C)),
+            InstructionType::BNE => self.op_branch(instr, !self.regs.test_flag(Flag::Z)),
+            InstructionType::BEQ => self.op_branch(instr, self.regs.test_flag(Flag::Z)),
+            InstructionType::BPL => self.op_branch(instr, !self.regs.test_flag(Flag::N)),
+            InstructionType::BMI => self.op_branch(instr, self.regs.test_flag(Flag::N)),
+            InstructionType::BVC => self.op_branch(instr, !self.regs.test_flag(Flag::V)),
+            InstructionType::BVS => self.op_branch(instr, self.regs.test_flag(Flag::V)),
+            InstructionType::BRA => self.op_branch(instr, true),
             _ => todo!(),
         }
     }
@@ -850,4 +859,23 @@ where
         self.tick_bus(2)?;
         Ok(())
     }
+
+    /// (Conditional) branch instructions, except BBS/BBC
+    fn op_branch(&mut self, instr: &Instruction, take: bool) -> Result<()> {
+        if !take {
+            // Branch not taken
+            return Ok(());
+        }
+
+        // Branch taken
+        let newpc = self
+            .regs
+            .read(Register::PC)
+            .wrapping_add_signed(instr.imm8(0) as i8 as i16);
+        self.regs.write(Register::PC, newpc);
+
+        // Internal cycles
+        self.tick_bus(2)?;
+        Ok(())
+    }
 }
diff --git a/src/test/processortests_spc700.rs b/src/test/processortests_spc700.rs
@@ -193,7 +193,7 @@ cpu_test!(instr_0c, 0x0c);
 cpu_test!(instr_0d, 0x0d);
 //cpu_test!(instr_0e, 0x0e);
 //cpu_test!(instr_0f, 0x0f);
-//cpu_test!(instr_10, 0x10);
+cpu_test!(instr_10, 0x10);
 cpu_test!(instr_11, 0x11);
 cpu_test!(instr_12, 0x12);
 cpu_test_no_trace!(instr_13, 0x13);
@@ -228,8 +228,8 @@ cpu_test_no_trace!(instr_29, 0x29);
 //cpu_test!(instr_2c, 0x2c);
 cpu_test!(instr_2d, 0x2d);
 //cpu_test!(instr_2e, 0x2e);
-//cpu_test!(instr_2f, 0x2f);
-//cpu_test!(instr_30, 0x30);
+cpu_test!(instr_2f, 0x2f);
+cpu_test!(instr_30, 0x30);
 cpu_test!(instr_31, 0x31);
 cpu_test!(instr_32, 0x32);
 cpu_test_no_trace!(instr_33, 0x33);
@@ -265,7 +265,7 @@ cpu_test!(instr_4c, 0x4c);
 cpu_test!(instr_4d, 0x4d);
 //cpu_test!(instr_4e, 0x4e);
 //cpu_test!(instr_4f, 0x4f);
-//cpu_test!(instr_50, 0x50);
+cpu_test!(instr_50, 0x50);
 cpu_test!(instr_51, 0x51);
 cpu_test!(instr_52, 0x52);
 cpu_test_no_trace!(instr_53, 0x53);
@@ -300,7 +300,7 @@ cpu_test_no_trace!(instr_69, 0x69);
 cpu_test!(instr_6d, 0x6d);
 //cpu_test!(instr_6e, 0x6e);
 //cpu_test!(instr_6f, 0x6f);
-//cpu_test!(instr_70, 0x70);
+cpu_test!(instr_70, 0x70);
 cpu_test!(instr_71, 0x71);
 cpu_test!(instr_72, 0x72);
 cpu_test_no_trace!(instr_73, 0x73);
@@ -334,7 +334,7 @@ cpu_test!(instr_8c, 0x8c);
 cpu_test!(instr_8d, 0x8d);
 cpu_test!(instr_8e, 0x8e);
 cpu_test!(instr_8f, 0x8f);
-//cpu_test!(instr_90, 0x90);
+cpu_test!(instr_90, 0x90);
 cpu_test!(instr_91, 0x91);
 cpu_test!(instr_92, 0x92);
 cpu_test_no_trace!(instr_93, 0x93);
@@ -369,7 +369,7 @@ cpu_test!(instr_ad, 0xad);
 cpu_test!(instr_ae, 0xae);
 // Wait during fetch
 cpu_test_no_trace!(instr_af, 0xaf);
-//cpu_test!(instr_b0, 0xb0);
+cpu_test!(instr_b0, 0xb0);
 cpu_test!(instr_b1, 0xb1);
 cpu_test!(instr_b2, 0xb2);
 cpu_test_no_trace!(instr_b3, 0xb3);
@@ -402,7 +402,7 @@ cpu_test!(instr_cc, 0xcc);
 cpu_test!(instr_cd, 0xcd);
 cpu_test!(instr_ce, 0xce);
 //cpu_test!(instr_cf, 0xcf);
-//cpu_test!(instr_d0, 0xd0);
+cpu_test!(instr_d0, 0xd0);
 cpu_test!(instr_d1, 0xd1);
 cpu_test!(instr_d2, 0xd2);
 cpu_test_no_trace!(instr_d3, 0xd3);
@@ -435,7 +435,7 @@ cpu_test!(instr_ec, 0xec);
 cpu_test!(instr_ed, 0xed);
 cpu_test!(instr_ee, 0xee);
 //cpu_test!(instr_ef, 0xef);
-//cpu_test!(instr_f0, 0xf0);
+cpu_test!(instr_f0, 0xf0);
 cpu_test!(instr_f1, 0xf1);
 cpu_test!(instr_f2, 0xf2);
 cpu_test_no_trace!(instr_f3, 0xf3);