mu - Soul of a tiny new machine. More thorough tests → More comprehensible and rewrite-friendly software → More resilient society.

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Diffstat (limited to 'linux/124next-token.subx')

0 files changed, 0 insertions, 0 deletions

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> <title>Mu - apps/ex9.subx</title> <meta name="Generator" content="Vim/8.1"> <meta name="plugin-version" content="vim8.1_v1"> <meta name="syntax" content="none"> <meta name="settings" content="number_lines,use_css,no_foldcolumn,expand_tabs,line_ids,prevent_copy="> <meta name="colorscheme" content="minimal-light"> <style type="text/css">  </style> <script type='text/javascript'>  </script> </head> <body onload='JumpToLine();'> <a href='https://github.com/akkartik/mu/blob/master/apps/ex9.subx'>https://github.com/akkartik/mu/blob/master/apps/ex9.subx</a> <pre id='vimCodeElement'> 1 # Example showing arg order on the stack. 2 # 3 # Show difference between ascii codes of first letter of first arg and first 4 # letter of second arg. 5 # 6 # To run: 7 # $ ./bootstrap translate init.linux apps/ex9.subx -o apps/ex9 8 # $ ./bootstrap run apps/ex9 z x 9 # Expected result: 10 # $ echo $? 11 # 2 12 # 13 # At the start of a SubX program: 14 # argc: *esp 15 # argv[0]: *(esp+4) 16 # argv[1]: *(esp+8) 17 # ... 18 # Locals start from esp-4 downwards. 19 20 == code 21 # instruction effective address register displacement immediate 22 # . op subop mod rm32 base index scale r32 23 # . 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 24 25 Entry: 26 # . prologue 27 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp 28 # ascii-difference(argv[1], argv[2]) 29 # . . push argv[2] 30 ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 0xc/disp8 . # push *(ebp+12) 31 # . . push argv[1] 32 ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 8/disp8 . # push *(ebp+8) 33 # . . call 34 e8/call <a href='ex9.subx.html#L41'>ascii-difference</a>/disp32 35 # . . discard args 36 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp 37 # exit(eax) 38 89/copy 3/mod/direct 3/rm32/ebx . . . 0/r32/eax . . # copy eax to ebx 39 e8/call syscall_exit/disp32 40 41 ascii-difference: # (s1, s2): null-terminated ascii strings 42 # a = first letter of s1 (ecx) 43 8b/copy 1/mod/*+disp8 4/rm32/sib 4/base/esp 4/index/none . 0/r32/eax 4/disp8 . # copy *(esp+4) to eax 44 8b/copy 0/mod/indirect 0/rm32/eax . . . 0/r32/eax . . # copy *eax to eax 45 # b = first letter of s2 (edx) 46 8b/copy 1/mod/*+disp8 4/rm32/sib 4/base/esp 4/index/none . 1/r32/ecx 8/disp8 # copy *(esp+8) to ecx 47 8b/copy 0/mod/indirect 1/rm32/ecx . . . 1/r32/ecx . . # copy *ecx to ecx 48 # a-b 49 29/subtract 3/mod/direct 0/rm32/eax . . . 1/r32/ecx . . # subtract ecx from eax 50 c3/return 51 52 # . . vim:nowrap:textwidth=0 </pre> </body> </html>


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