1 files changed, 40 insertions, 0 deletions

diff --git a/emu/6502.c b/emu/6502.c
index 8b24901..5baaf32 100644
--- a/emu/6502.c
+++ b/emu/6502.c
@@ -178,6 +178,8 @@ void cpu_6502_step( cpu_6502_t *cpu )
 {
 	uint8_t opcode;
 	uint8_t operand8;
+	uint16_t operand16;
+	uint16_t tmp;
 	
 	opcode = cpu_6502_read_byte( cpu, cpu->PC );
 	cpu->PC++;
@@ -230,6 +232,44 @@ void cpu_6502_step( cpu_6502_t *cpu )
 			cpu->A = cpu_6502_read_byte( cpu, operand8 );
 			update_negative_and_sign( cpu, cpu->A );
 			break;
+		
+		case STX_ABS:
+			operand16 = cpu_6502_read_word( cpu, cpu->PC );
+			cpu->PC += 2;
+			cpu_6502_write_word( cpu, operand16, cpu->X );
+			break;
+		
+		case DEY_IMPL:
+			cpu->Y--;
+			update_negative_and_sign( cpu, cpu->Y );
+			break;
+			
+		case ROL_ACC:
+			tmp = ( cpu->A << 1 ) | is_carry( cpu );
+			if( tmp & 0xFF00 ) {
+				cpu->PS |= PS_C;
+			} else {
+				cpu->PS &= ~PS_C;
+			}
+			cpu->A = tmp & 0xFF;
+			update_negative_and_sign( cpu, cpu->A );
+			break;
+		
+		case BNE_REL:
+			operand8 = cpu_6502_read_byte( cpu, cpu->PC );
+			cpu->PC++;
+			if( !is_zero( cpu ) ) {
+				cpu->PC += (int8_t)operand8;
+			}
+			break;
+			
+		case BCC_REL:
+			operand8 = cpu_6502_read_byte( cpu, cpu->PC );
+			cpu->PC++;
+			if( !is_carry( cpu ) ) {
+				cpu->PC += (int8_t)operand8;
+			}
+			break;
 			
 		case JMP_ABS:
 			cpu->PC = cpu_6502_read_word( cpu, cpu->PC );