BBC (SPC700): Difference between revisions

Revision as of 18:23, 23 July 2023


Basic Info
Addressing Mode	Opcode	Length	Speed
	13	3 byte	when condition is false: 5 cycles when condition is true: 7 cycles
	33	3 byte	when condition is false: 5 cycles when condition is true: 7 cycles
	53	3 byte	when condition is false: 5 cycles when condition is true: 7 cycles
	73	3 byte	when condition is false: 5 cycles when condition is true: 7 cycles
	93	3 byte	when condition is false: 5 cycles when condition is true: 7 cycles
	B3	3 byte	when condition is false: 5 cycles when condition is true: 7 cycles
	D3	3 byte	when condition is false: 5 cycles when condition is true: 7 cycles
	F3	3 byte	when condition is false: 5 cycles when condition is true: 7 cycles


Flags Clobbered
N	V	P	B	H	I	Z	C
.	.	.	.	.	.	.	.

BBC (Branch on Bit Clear) is an SPC700 instruction that performs a branch when a bit in the direct page is clear. The direct page byte that bit lives in is the first operand. The bit within that byte is a function of the high nibble of the opcode. The target relative address to jump to is the second operand.

External Links

Official Super Nintendo development manual on BBC: Appendix C-8 of Book I

@@ Line 78: / Line 78: @@
 |}
-'''BBC''' (Branch on Bit Clear) is an [[SPC700]] instruction that performs a branch when the [[direct page flag]] is clear.
+'''BBC''' (Branch on Bit Clear) is an [[SPC700]] instruction that performs a branch when a bit in the [[direct page]] is clear.  The direct page byte that bit lives in is the first operand.  The bit within that byte is a function of the high nibble of the opcode.  The target relative address to jump to is the second operand.
 === See Also ===