S3C80M4 Datasheet, PDF (169/248 Pages) Samsung semiconductor – 8-BIT CMOS MICROCONTROLLERS USERS MANUAL

S3C80M4/F80M4
INSTRUCTION SET
PUSHUD — Push User Stack (Decrementing)
PUSHUD
dst,src
Operation:
IR ← IR – 1
dst ← src
This instruction is used to address user-defined stacks in the register file. PUSHUD decrements
the user stack pointer and loads the contents of the source into the register addressed by the
decremented stack pointer.
Flags:
No flags are affected.
Format:
opc
dst
src
Bytes
3
Cycles
8
Opcode
(Hex)
82
Addr Mode
dst src
IR
R
Example:
Given: Register 00H = 03H, register 01H = 05H, and register 02H = 1AH:
PUSHUD @00H,01H →
Register 00H = 02H, register 01H = 05H, register 02H = 05H
If the user stack pointer (register 00H, for example) contains the value 03H, the statement
"PUSHUD @00H,01H" decrements the user stack pointer by one, leaving the value 02H. The
01H register value, 05H, is then loaded into the register addressed by the decremented user
stack pointer.
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