#ip 4

; while (123 & 456 != 72);
00: seti 123 0 2
01: bani 2 456 2
02: eqri 2 72 2
03: addr 2 4 4
04: seti 0 0 4

05: seti 0 8 2          ; r2 = 0
; xref 30
06: bori 2 65536 5      ; r5 = r2 | 0x10000
07: seti 2238642 0 2    ; r2 = 2238642
; xref 27
08: bani 5 255 3        ; r3 = r5 & 0xff
09: addr 2 3 2          ; r2 = r2 + r3
10: bani 2 16777215 2   ; r2 = r2 & 0xffffff
11: muli 2 65899 2      ; r2 = r2 * 65899
12: bani 2 16777215 2   ; r2 = r2 & 0xffffff
; trash = r3
; keep = r2, r5

13: gtir 256 5 3        ; if (0x100 > r5)
14: addr 3 4 4          ; then
15: addi 4 1 4          ; (false) jr +1 (17)
16: seti 27 3 4         ; (true ) jp 27 (28)

; xref 16 (256 <= r5)
17: seti 0 8 3          ; r3 = 0

; while ((r3 + 1) * 0x100 <= r5) r3++
18: addi 3 1 1          ; r1 = r3 + 1
19: muli 1 256 1        ; r1 = r1 * 0x100
20: gtrr 1 5 1          ; if (r1 > r5)
21: addr 1 4 4          ; then
22: addi 4 1 4          ; ..
23: seti 25 4 4         ; ..
24: addi 3 1 3          ; (false) r3 = r3 + 1
25: seti 17 2 4         ; (false) jp 17 (18)

26: setr 3 9 5          ; (true ) r5 = r3
27: seti 7 9 4          ; (true ) jp 07 (08)

; xref 16 (256 > r5)
28: eqrr 2 0 3          ; if (r2 == r0)
29: addr 3 4 4          ; then
30: seti 5 0 4          ; (false) jp 05 (06)
                        ; (true ) exit

; ===== HIGH-LEVEL PSEUDOCODE =====

r2 = 0

do {
    r5 = r2 | 0x10000
    r2 = 2238642

    while (1) {
        // r2 = (r2 + r5) * 65899
        r2 = (((r2 + (r5 & 0xff)) & 0xffffff) * 65899) & 0xffffff

        if (0x100 > r5) break

        r3 = 0
        while ((r3 + 1) * 0x100 <= r5) r3++
        r5 = r3
    }
} while (r2 != r0)