Computer Hardware User's Guide

Call Subroutine CALL
13-85 Assembly Language Instructions
Syntax CALL src
Operation Next PC → *++SP
src → PC
Operands src long-immediate addressing mode
Opcode
31 24 23 16 8 7 015
01100 0
10 src
Description A call is performed. The next PC value is pushed onto the system stack. The
src operand is loaded into the PC. The src operand is assumed to be a 24-bit
unsigned-immediate operand. Since the CALL instruction takes 4 cycles to
execute, the pipeline is flushed.
Cycles 4
Status Bits LUF Unaffected
LV Unaffected
UF Unaffected
N Unaffected
Z Unaffected
V Unaffected
C Unaffected
OVM Operation is not affected by OVM bit value.
Example CALL 123456h
Before Instruction After Instruction
PC 0005 PC 123456
SP 809801 SP 809802
LUF 0 LUF 0
LV 0 LV 0
UF 0 UF 0
N 0 N 0
Z 0 Z 0
V 0 V 0
C 0 C 0
Data memory
809802h 6
Mode Bit