Call Ja - Lucent Technologies DSP1617 Information Manual

Information Manual
April 1998

call JA (

call subroutine direct)
(pr) ← (PC + 1)
(PC) ← (PC bits 15—12)(JA)
The subroutine at address JA (within the same 4 Kword page) is called. The subroutine return register (pr) is set to
PC + 1. The lower 12 bits of the PC are written with the 12-bit immediate value of JA. The upper 4 bits of the PC
remain unchanged (the call pt instruction is used for subroutine calls outside the current 4 Kword page).
Bit
15 14
Field
1 0
Note: The call JA instruction should not be placed in the last or next-to-last instruction before the boundary of a
4 Kword page. If the call is placed there, the program counter will have incremented to the next page and
the jump will be to the next page rather than to the desired current page.
Lucent Technologies Inc.
DSP1611/17/18/27/28/29 DIGITAL SIGNAL PROCESSOR
13 12
0 0
Words: 1
Cycles: 2
Group: Control
Addressing: Immediate
Flags affected: None
Interruptible: No
Cacheable: No
Format: 4
DRAFT COPY
Instruction Set Summary
11—0
JA
B-4