SX18AA100-I/DP ETC [List of Unclassifed Manufacturers], SX18AA100-I/DP Datasheet - Page 33

• Manufacturer Part Number: SX18AA100-I/DP
• Description: Configurable Communications Controllers with EE/Flash Program Memory, In-System Programming Capability and On-Chip Debug
• Manufacturer: ETC [List of Unclassifed Manufacturers]

15.12 Subroutine Operation
15.12.1 Push Operation
When a subroutine is called, the return address is
pushed onto the subroutine stack. Specifically, each
address in the stack is moved to the next lower level in
order to make room for the new address to be stored.
Stack 1 receives the contents of the program counter.
Stack 8 is overwritten with what was in Stack 7. The con-
tents of stack 8 are lost.
© 2000 Scenix Semiconductor, Inc. All rights reserved.
PC<10:0>
STACK 1
STACK 2
STACK 3
STACK 4
STACK 5
STACK 6
STACK 7
STACK 8
- 33 -
15.12.2 Pop Operation
When a return instruction is executed the subroutine
stack is popped. Specifically, the contents of Stack 1 are
copied into the program counter and the contents of each
stack level are moved to the next higher level. For exam-
ple, Stack 1 receives the contents of Stack 2, etc., until
Stack 7 is overwritten with the contents of Stack 8. Stack
8 is left unchanged, so the contents of Stack 8 are dupli-
cated in Stack 7.
SX18AC/SX20AC/SX28AC/SX18AC75/SX20AC75/SX28AC75
PC<10:0>
STACK 1
STACK 2
STACK 3
STACK 4
STACK 5
STACK 6
STACK 7
STACK 8
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