User guide

DS4830A User’s Guide
219
PUSH src Push Word to the Stack
Description: Increments the stack pointer (SP) and pushes a single word specified by src to the stack
(@SP).
Status Flags: None
Operation: SP  ++SP
Encoding: 15 0
f000
1101
ssss
ssss
Example(s): PUSH GR ; GR=0F3Fh
PUSH #40h
Stack Data:
xxxxh
0040h
 SP (after PUSH #40h)
0F3Fh
 SP (after PUSH GR)
xxxxh
 SP (initial)
xxxxh
RET Return from Subroutine
Description: RET pops a single word from the stack (@SP) into the Instruction Pointer (IP) and
decrements the stack pointer (SP). The decremented SP is saved as the new stack pointer
(SP).
Status Flags: None
Operation: IP  @ SP--
Encoding: 15 0
1000
1100
0000
1101
Example(s): RET
Code Execution:
Addr (IP)
Opcode
0311h
…
0312h
RET
0103h
…
Stack Data:
xxxxh
xxxxh
0103h
 SP (before RET)
xxxxh
 SP (after RET)
xxxxh