https://github.com/akkartik/mu/blob/master/run_one_test.subx
 1 # run a single test
 2 
 3 == code
 4 #   instruction                     effective address                                                   register    displacement    immediate
 5 # . op          subop               mod             rm32          base        index         scale       r32
 6 # . 1-3 bytes   3 bits              2 bits          3 bits        3 bits      3 bits        2 bits      2 bits      0/1/2/4 bytes   0/1/2/4 bytes
 7 
 8 Entry:
 9     # Heap = new-segment(64KB)
10     # . . push args
11     68/push  Heap/imm32
12     68/push  0x10000/imm32/64KB
13     # . . call
14     e8/call  new-segment/disp32
15     # . . discard args
16     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
17     # initialize-trace-stream(256KB)
18     # . . push args
19     68/push  0x40000/imm32/256KB
20     # . . call
21     e8/call  initialize-trace-stream/disp32
22     # . . discard args
23     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
24     # for debugging: run a single test
25     e8/call $TEST_NAME/disp32
26     8b/copy                         0/mod/indirect  5/rm32/.disp32            .             .           3/r32/ebx   Num-test-failures/disp32          # copy *Num-test-failures to ebx
27     b8/copy-to-eax  1/imm32/exit
28     cd/syscall  0x80/imm8
29 
30 # . . vim:nowrap:textwidth=0