6.5.3. FRAME PUSH

Use the FRAME PUSH directive to inform the assembler when the callee saves registers, normally at function entry. You can only use it within functions with FUNCTION and ENDFUNC or PROC and ENDP directives.

Syntax

There are two alternative syntaxes for FRAME PUSH:

FRAME PUSH {reglist}
FRAME PUSH n

where:

reglist

is a list of registers stored consecutively below the canonical frame address. There must be at least one register in the list.

n

is the number of bytes that the stack pointer moves.

Usage

FRAME PUSH is equivalent to a FRAME ADDRESS and a FRAME SAVE directive. You can use it when a single instruction saves registers and alters the stack pointer.

You must use FRAME PUSH immediately after the instruction it refers to.

The assembler calculates the new offset for the canonical frame address. It assumes that:

  • each ARM register pushed occupies four bytes on the stack

  • each VFP single-precision register pushed occupies four bytes on the stack, plus an extra four-byte word for each list.

See FRAME ADDRESS and FRAME SAVE.

Example

p   PROC ; Canonical frame address is sp + 0
    EXPORT  p
    PUSH    {r4-r6,lr}
         ; sp has moved relative to the canonical frame address,
         ; and registers r4, r5, r6 and lr are now on the stack
    FRAME PUSH {r4-r6,lr}
         ; Equivalent to:
         ; FRAME ADDRESS    sp,16       ; 16 bytes in {r4-r6,lr}
         ; FRAME SAVE    {r4-r6,lr},-16
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