S3C84E5/C84E9/P84E9

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

Cycles

Opcode

Addr Mode

 

 

(Hex)

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 (the 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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Samsung S3C84E5 user manual Pushud Push User Stack Decrementing, Ir ← Ir, Decremented stack pointer