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INSTRUCTION SET
POPUD
— Pop User Stack (Decrementing)
POPUD
dst,src
dst ← src
Operation:
IR ← IR – 1
This instruction is used for user-defined stacks in the register file. The contents of the register file
location addressed by the user stack pointer are loaded into the destination. The user stack
pointer is then decremented.
Flags:
No flags are affected.
Format:
opc
Example:
Given: Register 00H = 42H (user stack pointer register), register 42H = 6FH, and
register 02H = 70H:
POPUD
If general register 00H contains the value 42H and register 42H the value 6FH, the statement
"POPUD 02H,@00H" loads the contents of register 42H into the destination register 02H. The
user stack pointer is then decremented by one, leaving the value 41H.
6-64
src
dst
→
02H,@00H
Register 00H = 41H, register 02H = 6FH, register 42H = 6FH
S3C8248/C8245/P8245/C8247/C8249/P8249
Bytes
Cycles
Opcode
3
8
Addr Mode
(Hex)
dst
src
92
R
IR
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