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

	Commit message (Expand)	Author	Age	Files	Lines
*	7476	Kartik Agaram	2020-12-30	1	-1/+1
*	6958	Kartik Agaram	2020-10-05	1	-1/+1
*	6631	Kartik Agaram	2020-07-10	1	-0/+137

<!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 - linux/ex7.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/main/linux/ex7.subx'>https://github.com/akkartik/mu/blob/main/linux/ex7.subx</a> <pre id='vimCodeElement'> 1 # Example showing file syscalls. 2 # 3 # Create a file, open it for writing, write a character to it, close it, open 4 # it for reading, read a character from it, close it, delete it, and return 5 # the character read. 6 # 7 # To run: 8 # $ bootstrap/bootstrap translate ex7.subx -o ex7 9 # $ bootstrap/bootstrap run ex7 10 # Expected result: 11 # $ echo $? 12 # 97 13 14 == code 15 # instruction effective address register displacement immediate 16 # . op subop mod rm32 base index scale r32 17 # . 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 18 19 Entry: 20 # creat(Filename) 21 bb/copy-to-ebx <a href='ex7.subx.html#L94'>Filename</a>/imm32 22 b9/copy-to-ecx 0x180/imm32/fixed-perms 23 e8/call <a href='000init.subx.html#L53'>syscall_creat</a>/disp32 24 25 # stream = open(Filename, O_WRONLY, 0) # we can't use 'fd' because it looks like a hex byte 26 bb/copy-to-ebx <a href='ex7.subx.html#L94'>Filename</a>/imm32 27 b9/copy-to-ecx 1/imm32/wronly 28 ba/copy-to-edx 0x180/imm32/fixed-perms 29 e8/call <a href='000init.subx.html#L35'>syscall_open</a>/disp32 30 # save stream 31 bb/copy-to-ebx <a href='ex7.subx.html#L88'>Stream</a>/imm32 32 89/copy 0/mod/indirect 3/rm32/ebx . . . 0/r32/eax . . # copy eax to *ebx 33 34 # write(Stream, "a", 1) 35 # . load stream 36 bb/copy-to-ebx <a href='ex7.subx.html#L88'>Stream</a>/imm32 37 8b/copy 0/mod/indirect 3/rm32/ebx . . . 3/r32/ebx . . # copy *ebx to ebx 38 # . 39 b9/copy-to-ecx <a href='ex7.subx.html#L90'>A</a>/imm32 40 ba/copy-to-edx 1/imm32/size 41 e8/call <a href='000init.subx.html#L29'>syscall_write</a>/disp32 42 43 # close(Stream) 44 # . load stream 45 bb/copy-to-ebx <a href='ex7.subx.html#L88'>Stream</a>/imm32 46 8b/copy 0/mod/indirect 3/rm32/ebx . . . 3/r32/ebx . . # copy *ebx to ebx 47 # . 48 e8/call <a href='000init.subx.html#L41'>syscall_close</a>/disp32 49 50 # stream = open(Filename, O_RDONLY, 0) 51 bb/copy-to-ebx <a href='ex7.subx.html#L94'>Filename</a>/imm32 52 b9/copy-to-ecx 0/imm32/rdonly 53 ba/copy-to-edx 0x180/imm32/fixed-perms 54 e8/call <a href='000init.subx.html#L35'>syscall_open</a>/disp32 55 # . save Stream 56 bb/copy-to-ebx <a href='ex7.subx.html#L88'>Stream</a>/imm32 57 89/copy 0/mod/indirect 3/rm32/ebx . . . 0/r32/eax . . # copy eax to *ebx 58 59 # read(Stream, B, 1) 60 # . load stream 61 bb/copy-to-ebx <a href='ex7.subx.html#L88'>Stream</a>/imm32 62 8b/copy 0/mod/indirect 3/rm32/ebx . . . 3/r32/ebx . . # copy *ebx to ebx 63 # . 64 b9/copy-to-ecx <a href='ex7.subx.html#L92'>B</a>/imm32 65 ba/copy-to-edx 1/imm32/size 66 e8/call <a href='000init.subx.html#L23'>syscall_read</a>/disp32 67 68 # close(Stream) 69 # . load stream 70 bb/copy-to-ebx <a href='ex7.subx.html#L88'>Stream</a>/imm32 71 8b/copy 0/mod/indirect 3/rm32/ebx . . . 3/r32/ebx . . # copy *ebx to ebx 72 # 73 e8/call <a href='000init.subx.html#L41'>syscall_close</a>/disp32 74 75 # unlink(filename) 76 bb/copy-to-ebx <a href='ex7.subx.html#L94'>Filename</a>/imm32 77 e8/call <a href='000init.subx.html#L59'>syscall_unlink</a>/disp32 78 79 # exit(b) 80 # . load b 81 bb/copy-to-ebx <a href='ex7.subx.html#L92'>B</a>/imm32 82 8b/copy 0/mod/indirect 3/rm32/ebx . . . 3/r32/ebx . . # copy *ebx to ebx 83 # 84 e8/call <a href='000init.subx.html#L18'>syscall_exit</a>/disp32 85 86 == data 87 88 Stream: 89 0/imm32 90 A: 91 61/imm32/A 92 B: 93 0/imm32 94 Filename: 95 2e 66 6f 6f 00 00 00 00 96 # . f o o null 97 98 # . . vim:nowrap:textwidth=0 </pre> </body> </html>