J... - Jump (conditional) Instruction

The J... instruction actions a conditional jump which generally follows a CMP instruction or an action that sets the flags (like DIV, MUL etc..).
This command has 2 parts, Instruction, then either a Register, Immediate value or a memory address.
These 8 bit near jumps can jump up to 127 bytes forward or backward. Forward start at 0 to 79h, backward start from FF to 80h.

There are 32 J instructions, there can more than one letter following the J which denote the use. Many of these have the same or similar effects and therefore share the same Op Code number.

O = Overflow Flag

C = Carry Flag

S = Sign Flag

P = Parity Flag

N = Not that action

E = Equals

L = Lower than

G = Greater than

Z = Zero value

A = Above

B = Below

Syntax: JE 0x03 ; Jump if Equal 3 bytes forward.

Instructions in Op Code sequence

Op Code Instruction

70 JO

71 JNO

72 JB, JC, JNAE

73 JNB, JNC, JAE

74 JZ, JE

75 JNZ, JNE

76 JBE, JNA

77 JA, JNBE

78 JS

79 JNS

7A JP, JPE

7B JNP, JPO

7C JL, JNGE

7D JNL, JGE

7E JLE, JNG

7F JG, JNLE

E3 JCXZ, JECXZ

Instructions according to use

Op Code Instruction

Carry JC, JNC

Overflow JO, JNO

Parity JP, JNP, JPE, JPO

Sign JS, JNS

Lower JL, JB, JLE, JNA, JNG, JNGE, JNAE, JBE

Greater JG, JA, JGE, JNB, JNL, JNLE, JNBE, JAE

Equal JE, JNE

Zero JZ, JNZ, JCXZ, JECXZ

Op Code	Instruction
70	JO
71	JNO
72	JB, JC, JNAE
73	JNB, JNC, JAE
74	JZ, JE
75	JNZ, JNE
76	JBE, JNA
77	JA, JNBE
78	JS
79	JNS
7A	JP, JPE
7B	JNP, JPO
7C	JL, JNGE
7D	JNL, JGE
7E	JLE, JNG
7F	JG, JNLE
E3	JCXZ, JECXZ

Op Code	Instruction
Carry	JC, JNC
Overflow	JO, JNO
Parity	JP, JNP, JPE, JPO
Sign	JS, JNS
Lower	JL, JB, JLE, JNA, JNG, JNGE, JNAE, JBE
Greater	JG, JA, JGE, JNB, JNL, JNLE, JNBE, JAE
Equal	JE, JNE
Zero	JZ, JNZ, JCXZ, JECXZ