`hex.cmp` (arity 5)¶

Three-way compare on hex nibbles: jumps to lt if a<b, eq if a==b, gt if a>b. a, b are hexes; lt, eq, gt are addresses.

Signature¶

def cmp a, b, lt, eq, gt @ ret, _eq, _gt, jumper_to_return_table, __lt, __eq, __gt < .cmp.dst, .tables.ret { ... }

Defined in hex/cond_jumps.fj — lines 81–109 (view on GitHub).

Complexity¶

Time: 3@+8
Space: 3@+30

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

Requires init¶

The following must be initialised before this macro is invoked:

hex.cmp.init (or hex.init)

Source¶

Click to view the macro body

def cmp a, b, lt, eq, gt \
        @ ret, _eq, _gt, jumper_to_return_table, __lt, __eq, __gt \
        < .cmp.dst, .tables.ret {
    //part1
    .xor .cmp.dst  , a
    .xor .cmp.dst+4, b
    wflip .tables.ret+w, ret, .cmp.dst


    pad 4
    //part2
  ret:
    wflip .tables.ret+w, ret, jumper_to_return_table //part3
    .tables.ret+dbit  ;_eq
    .tables.ret+dbit+1;_gt

  _eq:  jumper_to_return_table+dbit  ;ret       //(part2.5)
  _gt:  jumper_to_return_table+dbit+1;ret

  jumper_to_return_table:
    //part4
    ;__lt

    pad 4
    //part5
  __lt:                               ;lt
  __eq:  jumper_to_return_table+dbit  ;eq
  __gt:  jumper_to_return_table+dbit+1;gt
}

Depends on¶

hex.xor/2

Used by¶

Example uses¶

hex.cmp in hex/cond_jumps.fj
hex.cmp.cmp_eq_next in hex/cond_jumps.fj

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