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The 68000's Instruction Set
Application: Any unknown pattern of bits read by the 68000 during an instruc-
tion read phase will cause an illegal instruction trap. The ILLEGAL
instruction can be thought of as an official illegal instruction. It
can be used to test the illegal instruction trap and will always be
an illegal instruction in any future enhancement of the 68000.
Condition codes: X N Z V C
- - - - -
JMP Jump (unconditionally)
Operation: [PC] ← destination
Syntax: JMP <ea>
Attributes: Unsized
Description: Program execution continues at the effective address specified by
the instruction.
Application: Apart from a simple unconditional jump to an address fixed at
compile time (i.e., JMP label), the JMP instruction is useful for
the calculation of dynamic or computed jumps. For example, the
instruction JMP (A0,D0.L) jumps to the location pointed at by
the contents of address register A0, offset by the contents of data
register D0. Note that JMP provides several addressing modes,
while BRA provides a single addressing mode (i.e., PC relative).
Condition codes: X N Z V C
- - - - -
Source operand addressing modes
JSR Jump to subroutine
Operation: [SP] ← [SP] - 4; [M([SP])] ← [PC]
[PC]
← destination
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