hex.ptr_sub

ptr[:w/4] -= value * 2w (retreat ptr by value)
@note: The complexity is calculated with n_const=2, and for log(w) in 16,32,64,128.

Signature

def ptr_sub ptr, value { ... }

Defined in hex/pointers/pointer_arithmetics.fj — lines 35–37 (view on GitHub).

Complexity

• Time: 13@+35

• Space: w(0.375@ + 3.25)  + 7.5@+106

See the complexity glossary for what @, w, dw, dbit, n mean.

Requires init

The following must be initialised before this macro is invoked:

• hex.sub.init (or hex.init)

Source

Click to view the macro body

def ptr_sub ptr, value {
    hex.sub_constant w/4, ptr, value * dw
}

Depends on

• hex.sub_constant

Used by

• hex.read_byte/3

• hex.read_hex/3

• hex.sp_sub

• hex.write_byte/3

• hex.write_hex/3

• hex.xor_byte_to_ptr/3

• hex.xor_hex_to_ptr/3

Example uses

• hex.xor_hex_to_ptr in hex/pointers/xor_to_pointer.fj

• hex.xor_byte_to_ptr in hex/pointers/xor_to_pointer.fj

• hex.read_hex in hex/pointers/read_pointers.fj

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