5.2.3. ADD and SUB, sp

Increment or decrement sp by an immediate constant.

Syntax

ADD sp, #expr
SUB sp, #expr

where:

expr

is an expression that evaluates (at assembly time) to a multiple of 4 in the range –508 to +508.

Usage

This instruction adds the value of expr to the value from Rp, and places the result in Rd.

Note

An ADD instruction with a negative value for expr assembles to the corresponding SUB instruction with a positive constant. A SUB instruction with a negative value for expr assembles to the corresponding ADD instruction with a positive constant.

Be aware of this when looking at disassembly listings.

Condition flags

This instruction does not affect the flags.

Architectures

This instruction is available in all T variants of the ARM architecture.

Examples

    ADD sp,#312 
    SUB sp,#96
    SUB sp,#abc+8   ; abc + 8 must evaluate at assembly time to
                    ; a multiple of 4 in the range –508 to +508
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