Samsung S3F80JB - Manual (Page 195)

S3F80JB INSTRUCTION SET
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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:
Bytes Cycles Opcode
(Hex)
Addr Mode
dst src
opc dst src 3 8 82 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.