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CALA
Call Subroutine at Location Specified by Accumulator
7-58
Syntax CALA
Operands None
Opcode
0123456789101112131415
0000110001111101
Execution PC + 1 → TOS
ACC(15:0) → PC
Status Bits None
Description The current program counter (PC) is incremented and pushed onto the top of
the stack (TOS). Then, the contents of the lower half of the accumulator are
loaded into the PC. Execution continues at this address.
The CALA instruction is used to perform computed subroutine calls.
Words 1
Cycles for a Single CALA Instruction
ROM
DARAM SARAM External
4 4 4 4+3p
Note: When this instruction reaches the execute phase of the pipeline, two additional instruc-
tion words have entered the pipeline. When the PC discontinuity is taken, these two
instruction words are discarded.
Example CALA
Before Instruction After Instruction
PC 25h PC 83h
ACC 83h ACC 83h
TOS 100h TOS 26h
Cycles