We've just updated MediaWiki and its underlying software. If anything doesn't look or work quite right, please mention it to us. --RanAS
CBNE (SPC700): Difference between revisions
From SnesLab
(moved tables up) |
(superscripted 3) |
||
| (13 intermediate revisions by the same user not shown) | |||
| Line 1: | Line 1: | ||
{| class="wikitable" style="float:right;clear:right;width: | {| class="wikitable" style="float:right;clear:right;width:60%" | ||
!colspan="8"|Basic Info | !colspan="8"|Basic Info | ||
|+ | |+ | ||
| Line 7: | Line 7: | ||
|'''Speed''' | |'''Speed''' | ||
|+ | |+ | ||
| | |[[Direct Page]] / [[Program Counter Relative]] | ||
|2E | |2E | ||
|3 bytes | |3 bytes | ||
| Line 13: | Line 13: | ||
when condition is true: 7 cycles | when condition is true: 7 cycles | ||
|+ | |+ | ||
| | |[[Direct Page Indexed by X]] / [[Program Counter Relative]] | ||
|DE | |DE | ||
|3 bytes | |3 bytes | ||
| Line 21: | Line 21: | ||
{| class="wikitable" style="float:right;clear:right;width:30%" | {| class="wikitable" style="float:right;clear:right;width:30%" | ||
!colspan="8"|Flags | !colspan="8"|Flags Affected | ||
|+ | |+ | ||
|N | |[[Negative Flag|N]] | ||
|V | |[[Overflow Flag|V]] | ||
|P | |[[Direct Page Flag|P]] | ||
|B | |[[Break Flag|B]] | ||
|H | |[[Half-Carry Flag|H]] | ||
|I | |[[Interrupt Enable Flag|I]] | ||
|Z | |[[Zero Flag|Z]] | ||
|C | |[[Carry Flag|C]] | ||
|+ | |+ | ||
|. | |. | ||
| Line 42: | Line 42: | ||
|} | |} | ||
'''CBNE''' is an [[SPC700]] instruction that performs a comparison between the accumulator and a direct page value and then branches if they are not equal. | '''CBNE''' (Compare Branch Not Equal) is an [[SPC700]] instruction that performs a comparison between the [[accumulator]] and a [[direct page]] value and then branches if they are not equal. The direct page index is the first operand and also the first byte immediately following the opcode, and the relative branch offset is the second operand, the second byte following the opcode.<sup>[3]</sup> | ||
No flags are affected. | |||
==== Syntax ==== | |||
<pre> | |||
CBNE dp, rel | |||
CBNE dp+X, rel | |||
</pre> | |||
Where rel is given in two's complement. | |||
=== See Also === | === See Also === | ||
| Line 49: | Line 59: | ||
=== External Links === | === External Links === | ||
# Official Super Nintendo development manual on CBNE: Table C-15, [https://archive.org/details/SNESDevManual/book1/page/n233 Appendix C-8 of book I] | |||
# anomie: https://github.com/yupferris/TasmShiz/blob/8fabc9764c33a7ae2520a76d80ed7220bb939f12/spc700.txt#L372 | |||
# lbid: https://github.com/yupferris/TasmShiz/blob/8fabc9764c33a7ae2520a76d80ed7220bb939f12/spc700.txt#L270 | |||
[[Category:ASM]] | [[Category:ASM]] | ||
[[Category:SPC700]] | [[Category:SPC700]] | ||
[[Category:Branching Commands]] | [[Category:Branching Commands]] | ||
Latest revision as of 19:31, 15 August 2024
| Basic Info | |||||||
|---|---|---|---|---|---|---|---|
| Addressing Mode | Opcode | Length | Speed | ||||
| Direct Page / Program Counter Relative | 2E | 3 bytes | when condition is false: 5 cycles
when condition is true: 7 cycles |
||||
| Direct Page Indexed by X / Program Counter Relative | DE | 3 bytes | when condition is false: 6 cycles
when condition is true: 8 cycles | ||||
| Flags Affected | |||||||
|---|---|---|---|---|---|---|---|
| N | V | P | B | H | I | Z | C |
| . | . | . | . | . | . | . | . |
CBNE (Compare Branch Not Equal) is an SPC700 instruction that performs a comparison between the accumulator and a direct page value and then branches if they are not equal. The direct page index is the first operand and also the first byte immediately following the opcode, and the relative branch offset is the second operand, the second byte following the opcode.[3]
No flags are affected.
Syntax
CBNE dp, rel CBNE dp+X, rel
Where rel is given in two's complement.
See Also
External Links
- Official Super Nintendo development manual on CBNE: Table C-15, Appendix C-8 of book I
- anomie: https://github.com/yupferris/TasmShiz/blob/8fabc9764c33a7ae2520a76d80ed7220bb939f12/spc700.txt#L372
- lbid: https://github.com/yupferris/TasmShiz/blob/8fabc9764c33a7ae2520a76d80ed7220bb939f12/spc700.txt#L270