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PUSH Instruction UM018809-0611

140

ZNEO

CPU Core

User Manual

PUSH

Definition

PUSH Value

Syntax

PUSH src

Operation

Description

The PUSH instruction decrements the Stack Pointer (R15) by 1, 2, or 4 and loads the source

value into the byte, word, or quad pointed to by the Stack Pointer.

The default data size is 32 bits. Byte (8-bit) or Word (16-bit) data size can be selected by adding

a .B or .W, suffix, respectively, to the PUSH mnemonic.

When a 32-bit value is pushed into an 8- or 16-bit stack location, the value is truncated to fit the

destination size. When an 8- or 16-bit immediate value is pushed into a larger location, it is

always sign extended.

PUSH is implemented using LD register-indirect opcodes with predecrement. See LD for more

instructions that load and store data.

Flags

Flags are not affected by this instruction.

PUSH:

 SP – 4

(SP)

 src

PUSH.B:

 SP – 1

(SP)

 src

PUSH.W:

 SP – 2

(SP)

 src

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Zilog Z16F2810 Manuale Utente Pagina 156