BVS: Difference between revisions

Latest revision as of 17:42, 23 August 2024


Basic Info
Addressing Mode	Opcode	Length	Speed
Program Counter Relative	70	2 bytes	2 cycles*


Flags Affected
N	V	M	X	D	I	Z	C
.	.	.	.	.	.	.	.

BVS is a 65x instruction that performs a branch if the overflow flag is set.

If the overflow flag is clear, control simply falls through to the next instruction.

No flags are affected.

Syntax

BVS nearlabel

Cycle Penalties

BVS takes one extra cycle if the branch is taken
BVS takes another extra cycle if that branch taken crosses a page boundary in emulation mode.

External Links

Eyes & Lichty, page 440 on BVS
Labiak, page 129 on BVS
4.1.2.7 on MCS6500 Manual, page 41 on BVS
Carr, page 253 on BVS
Leventhal, page 3-51 on BVS
snes9x implementation of BVS: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L1400

@@ Line 1: / Line 1: @@
-'''BVS''' is a 65x instruction that performs a branch if the [[overflow flag]] is set.
+{| class="wikitable" style="float:right;clear:right;width:40%"
+!colspan="8"|Basic Info
+|+
+|'''Addressing Mode'''
+|'''Opcode'''
+|'''Length'''
+|'''Speed'''
+|+
+|[[Program Counter Relative]]
+|70
+|2 bytes
+|2 cycles*
+|}
 {| class="wikitable" style="float:right;clear:right;width:30%"
-!colspan="9"|Flags Clobbered
+!colspan="9"|Flags Affected
 |+
-|N
+|[[Negative Flag|N]]
-|V
+|[[Overflow Flag|V]]
-|M
+|[[M Flag|M]]
-|X
+|[[X Flag|X]]
-|D
+|[[Decimal Flag|D]]
-|I
+|[[I Flag|I]]
-|Z
+|[[Zero Flag|Z]]
-|C
+|[[Carry Flag|C]]
 |+
 |.
@@ Line 22: / Line 34: @@
 |.
 |}
+'''BVS''' is a 65x instruction that performs a branch if the [[overflow flag]] is set.
+If the overflow flag is clear, control simply falls through to the next instruction.
+No flags are affected.
+==== Syntax ====
+<pre>
+BVS nearlabel
+</pre>
+==== Cycle Penalties ====
+* BVS takes one extra cycle if the branch is taken
+* BVS takes another extra cycle if that branch taken crosses a page boundary in [[emulation mode]].
+=== See Also ===
+* [[BVC]]
+* [[BVS (SPC700)]]
+* [[BRA]]
+* [[CLV]]
+=== External Links ===
+* [[Eyes & Lichty]], [https://archive.org/details/0893037893ProgrammingThe65816/page/440 page 440] on BVS
+* [[Labiak]], [https://archive.org/details/Programming_the_65816/page/n139 page 129] on BVS
+* 4.1.2.7 on [[MCS6500 Manual]], [https://archive.org/details/mos_microcomputers_programming_manual/page/n56 page 41] on BVS
+* [[Carr]], [https://archive.org/details/6502UsersManual/page/n266 page 253] on BVS
+* [[Leventhal]], [https://archive.org/details/6502-assembly-language-programming/page/n100 page 3-51] on BVS
+* snes9x implementation of BVS: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L1400
 [[Category:ASM]]
 [[Category:Inherited from 6502]]
+[[Category:Conditional Branches]]
+[[Category:Two-byte Instructions]]