Texas Instruments MSP430x4xx - Manual (Page 89)

Instruction Set
3-55 RISC 16−Bit CPU
PUSH[.W] Push word onto stack
PUSH.B Push byte onto stack
Syntax PUSH src or PUSH.W src
PUSH.B src
Operation SP − 2
→
SP
src
→
@SP
Description The stack pointer is decremented by two, then the source operand is moved
to the RAM word addressed by the stack pointer (TOS).
Status Bits Status bits are not affected.
Mode Bits OSCOFF, CPUOFF, and GIE are not affected.
Example The contents of the status register and R8 are saved on the stack.
PUSH SR ; save status register
PUSH R8 ; save R8
Example The contents of the peripheral TCDAT is saved on the stack.
PUSH.B &TCDAT ; save data from 8-bit peripheral module,
; address TCDAT, onto stack
Note: The System Stack Pointer
The system stack pointer (SP) is always decremented by two, independent
of the byte suffix.