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MAXQ7667 User’s Guide

{L/S}JUMP src Unconditional {Long/Short} Jump

Description:

Performs an unconditional jump as determined by the src specifier. The JUMP instruction uses an 8-bit immediate

src to perform a relative jump (IP +127/-128 words). The JUMP instruction uses a 16-bit immediate src to perform

an absolute JUMP to the specified 16-bit address. The PFX[0] register is used to supply the high byte of a 16-bit

immediate address for the absolute JUMP. Using the optional 'L' prefix (i.e., LJUMP) results in an absolute long jump

and use of the PFX[0] register. Using the optional 'S' prefix (i.e., SJUMP) attempts to generate a relative short jump,

but is flagged by the assembler if the destination is out of range. Specifying an internal register src (no matter

whether 8-bit or 16-bit) always produces an absolute JUMP to a 16-bit address, thus the 'L' and 'S' prefixes should

not be used. The PFX[n] register value is used to supply the high address byte when an 8-bit register src is speci-

fied.

Status Flags: None

Operation: IP ← src Absolute JUMP

← IP + src Relative JUMP

Encoding: 15 0

Example(s): JUMP label1 ; relative jump to label1 (must be within range

; IP +127/-128 words)

JUMP label1 ; absolute jump to label1= 0400h

; MOVE PFX[0], #04h

; JUMP #00h

JUMP DP[0] ; absolute jump to addr16 DP[0]

JUMP M0[0] ; assume M0[0] is an 8-bit register

; absolute jump to addr16

; high(addr16)=00h (PFX[0])

; low (addr16)=M0[0]

LJUMP label1 ; label=0120h and is relative to this instruction

; absolute jump is forced by use of 'L' prefix

; MOVE PFX[0], #01h

; JUMP #20h

SJUMP label1 ; relative offset for label1 calculated and used

; if label1 is not relative, assembler will generate an error

SJUMP #10h ; relative offset of #10h is used directly by the JUMP

f000

1100

ssss

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