Zilog Z16F2810 - Manual (Page 156)

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

SP – 4

(SP)

src
PUSH.B:
SP

SP – 1

(SP)

src
PUSH.W:
SP

SP – 2

(SP)

src