XB pma,*,ARPn
6-369
XB pma,*,ARPn C2xLP Source-Compatible Branch with ARP Modification
SYNTAX OPTIONS OPCODE OBJMODE RPT CYC
XB pma,*,ARPn 0011 1110 0111 0nnn
CCCC CCCC CCCC CCCC
1 − 4
Operands pma 16-bit immediate program -memory address,
can only access high 64K of program space range (0x3F0000 to 0x3FFFFF)
ARPn 3-bit auxiliary register pointer (ARP0 to ARP7)
Description Unconditional branch with ARP modification by loading the low 16 bits of PC
with the 16-bit immediate value ”pma” and forcing the upper 6 bits of the PC
to 0x3F. Also, change the auxiliary register pointer as specified by the
“ARPn” operand:
PC = 0x3F:pma;
ARP = n;
Note: This branch instruction can only branch to a location located in the upper 64K range of
program space (0x3F0000 to 0x3FFFFF).
Flags and
Modes
None
Repeat This instruction is not repeatable. If this instruction follows the RPT
instruction, it resets the repeat counter (RPTC) and executes only once.
Example
; Branch to SubA and set ARP. Load ACC with pointer pointed to
; by ARP and return to. This example only works for code
; located in upper 64K of program space:
XB SubA,*,ARP1 ; Branch to SubA with ARP pointing
; to XAR1
SubReturn:
.
SubA: ; Subroutine A:
MOVL ACC,* ; Load ACC with contents
; pointed to by XAR(ARP)
XB SubReturn,UNC ; Return unconditionally
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