BEQ: Difference between revisions

Latest revision as of 04:39, 6 December 2023


Basic Info
Addressing Mode	Opcode	Length	Speed
Program Counter Relative	F0	2 byte	2 cycles


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

BEQ (Branch if Equal) is a 65x instruction that performs a jump if the zero flag is set.

Cycle Penalties

BEQ takes an extra cycle if the branch is taken
BEQ takes another extra cycle if the branch taken crosses a page boundary in emulation mode

External Links

Eyes & Lichty page 430, on BEQ: https://archive.org/details/0893037893ProgrammingThe65816/page/n456
Labiak page 120 on BEQ: https://archive.org/details/Programming_the_65816/page/n130
MCS6500 Manual page 41 on BEQ: https://archive.org/details/mos_microcomputers_programming_manual/page/n56
Carr page 249 on BEQ: https://archive.org/details/6502UsersManual/page/n262
Leventhal page 3-44 on BEQ: https://archive.org/details/6502-assembly-language-programming/page/n93
snes9x implementation of BEQ: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L1370

@@ Line 1: / Line 1: @@
-'''BEQ''' (Branch if Equal) is a 65x instruction that performs a jump if the [[zero flag]] is set.
+{| class="wikitable" style="float:right;clear:right;width:40%"
-{| class="wikitable" style="float:right;clear:right;width:30%"
 !colspan="8"|Basic Info
 |+
@@ Line 9: / Line 7: @@
 |'''Speed'''
 |+
-|relative
+|[[Program Counter Relative]]
 |F0
 |2 byte
@@ Line 16: / Line 14: @@
 {| 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 36: / Line 34: @@
 |.
 |}
+'''BEQ''' (Branch if Equal) is a 65x instruction that performs a jump if the [[zero flag]] is set.
+===== Cycle Penalties =====
+* BEQ takes an extra cycle if the branch is taken
+* BEQ takes another extra cycle if the branch taken crosses a page boundary in [[emulation mode]]
 === See Also ===
 * [[BNE]]
+* [[BEQ (Super FX)]]
 === External Links ===
-* [[Eyes & Lichty]] page on BEQ: https://archive.org/details/0893037893ProgrammingThe65816/page/n456
+* [[Eyes & Lichty]] page 430, on BEQ: https://archive.org/details/0893037893ProgrammingThe65816/page/n456
-* [[Labiak]] page on BEQ: https://archive.org/details/Programming_the_65816/page/n130
+* [[Labiak]] page 120 on BEQ: https://archive.org/details/Programming_the_65816/page/n130
+* [[MCS6500 Manual]] page 41 on BEQ: https://archive.org/details/mos_microcomputers_programming_manual/page/n56
+* [[Carr]] page 249 on BEQ: https://archive.org/details/6502UsersManual/page/n262
+* [[Leventhal]] page 3-44 on BEQ: https://archive.org/details/6502-assembly-language-programming/page/n93
+* snes9x implementation of BEQ: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L1370
 [[Category:ASM]]
 [[Category:Inherited from 6502]]
+[[Category:Conditional Branches]]
+[[Category:Two-byte Instructions]]