overflow.xtl

1⍝!/usr/bin/env xetal
2⍝ What an 8-bit adder does with 100 + 100: the exact sum is 200, which
3⍝ does not fit in 8 signed bits, so the circuit answers -56; at 16
4⍝ bits it fits. Run with "just demo-lib Fixed overflow".
5ᶠˣ⁼u̲se< "Fixed"
6100 + 100                    ⍝ the evaluator's 64-bit Int
78 ᶠˣo̲verflow? 200            ⍝ 1: not in -128 to 127
88 ᶠˣw̲rap 200                 ⍝ what the 8-bit adder gives
98 ᶠˣb̲its 200                 ⍝ its bits: the top bit set, so negative
108 ᶠˣs̲at 200                  ⍝ a saturating adder would stop at 127
1116 ᶠˣw̲rap 200                ⍝ a 16-bit adder is fine
1216 ᶠˣh̲ex 200