jmp/jcc

The jump and jump conditional instructions (conditionally) jump to the given location by setting the program counter accordingly.

In the following, $\mathit{PC}$ denotes the address of the first byte after the current instruction, $\mathit{pc}$ is the program counter register, and $\mathit{pi}$ is the page-index register.

Instruction	Encoding	Semantics	Cycles
jmp pi	00 000 001	$\mathit{pc} \gets \mathit{pi}$	1
jcc imm8s161	00 ccc 11n imm8	$\mathit{pc} \gets \mathit{PC} + \mathit{sext}(\mathit{imm8})$ if the condition is met	22/53/84
jmp imm16	00 101 111 imm16	$\mathit{pc} \gets \mathit{imm16}$	3

1. There is no jump with false condition (ccc = 101, n = 1). Instead, we have jmp imm16.
2. 2 cycles for fall-through
3. 5 cycles if the upper address byte remains unchanged
4. 8 cycles if the upper address byte changes

Condition Codes

For jcc, there are the following conditions (inspired by x86):

Mnemonic	ccc	n	Condition	Description
jo	000	0	$\mathit{OF} = 1$	overflow
jb, jc, jnae	001	0	$\mathit{CF} = 1$	below / carry / not above or equal
je, jz	010	0	$\mathit{ZF} = 1$	equal / zero
jbe, jna	011	0	$\mathit{CF}\mid\mathit{ZF} = 1$	below or equal / not above
js	100	0	$\mathit{SF} = 1$	sign
jmp	101	0	$\mathit{true}$	unconditional
jl, jnge	110	0	$\mathit{SF}~^\wedge\mathit{OF} = 1$	less / not greater or equal
jle, jng	111	0	$(\mathit{SF}~^\wedge\mathit{OF})\mid\mathit{ZF} = 1$	less or equal / not greater
jno	000	1	$\mathit{OF} = 0$	not overflow
jnb, jnc, jae	001	1	$\mathit{CF} = 0$	not below / not carry / above or equal
jne, jnz	010	1	$\mathit{ZF} = 0$	not equal / not zero
jnbe, ja	011	1	$\mathit{CF}\mid\mathit{ZF} = 0$	not below or equal / above
jns	100	1	$\mathit{SF} = 0$	not sign
jnl, jge	110	1	$\mathit{SF}~^\wedge\mathit{OF} = 0$	not less / greater or equal
jnle, jg	111	1	$(\mathit{SF}~^\wedge\mathit{OF})\mid\mathit{ZF} = 0$	not less or equal / greater