JMP: Difference between revisions

Revision as of 03:14, 3 August 2024


Basic Info
Addressing Mode	Opcode	Length	Speed
Absolute	4C	3 bytes	3 cycles
Absolute Indirect	6C	3 bytes	5 cycles
Absolute Indexed Indirect	7C	3 bytes	6 cycles
Absolute Long	5C	4 bytes	4 cycles
Absolute Indirect Long	DC	3 bytes	6 cycles


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

JMP is a 65c816 instruction that performs an unconditional jump. This is analogous to GOTO in middle level programming languages.

Quirk

The NMOS 6502's opcode 6C sometimes behaves incorrectly. When doing an indirect jump, care must be taken to make sure the two-byte vector containing the absolute target address does not straddle a page boundary (that is, the vector is not located at $xxFF for any xx). Otherwise, byte zero ($xx00) of the page the vector begins in will be misused as the high byte of the target address instead of the first byte of the following page.

JMP is not relocatable. No flags are affected.

Syntax

JMP addr
JMP (addr)
JMP (addr, X)
JMP long
JML long
JMP [addr]
JML [addr]

External Links

Eyes & Lichty page 459, on JMP: https://archive.org/details/0893037893ProgrammingThe65816/page/459
Labiak page 145 on JMP: https://archive.org/details/Programming_the_65816/page/n155
MCS6500 Manual page 36 on JMP: https://archive.org/details/mos_microcomputers_programming_manual/page/n51
Carr page 261 on JMP: https://archive.org/details/6502UsersManual/page/n274
Leventhal page 3-69 on JMP: https://archive.org/details/6502-assembly-language-programming/page/n118
Pickens, John. http://www.6502.org/tutorials/6502opcodes.html#JMP

@@ Line 75: / Line 75: @@
 === See Also ===
 * [[BRA]]
+* [[BRL]]
 * [[LJMP (Super FX)]]