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<!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/202write-int.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/202write-int.subx'>https://github.com/akkartik/mu/blob/main/linux/202write-int.subx</a> <pre id='vimCodeElement'> 1 # write-int: add (the binary representation of) a single int to a stream 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 write-int: # out: (addr stream byte), n: int 9 # . prologue 10 55/push-ebp 11 89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp 12 # . save registers 13 50/push-eax 14 51/push-ecx 15 57/push-edi 16 # edi = out 17 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 7/r32/edi 8/disp8 . # copy *(ebp+8) to edi 18 # ecx = out->write 19 8b/copy 0/mod/indirect 7/rm32/edi . . . 1/r32/ecx . . # copy *edi to ecx 20 # if (out->write >= out->size) abort 21 3b/compare 1/mod/*+disp8 7/rm32/edi . . . 1/r32/ecx 8/disp8 . # compare ecx with *(edi+8) 22 7d/jump-if->= $write-int:abort/disp8 23 $write-int:to-stream: 24 # out->data[out->write] = n 25 8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 0/r32/eax 0xc/disp8 . # copy *(ebp+12) to eax 26 89/copy 1/mod/*+disp8 4/rm32/sib 7/base/edi 1/index/ecx . 0/r32/eax 0xc/disp8 . # copy eax to *(edi+ecx+12) 27 # out->write += 4 28 81 0/subop/add 0/mod/indirect 7/rm32/edi . . . . . 4/imm32 # add to *edi 29 $write-int:end: 30 # . restore registers 31 5f/pop-to-edi 32 59/pop-to-ecx 33 58/pop-to-eax 34 # . epilogue 35 89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp 36 5d/pop-to-ebp 37 c3/return 38 39 $write-int:abort: 40 # . _write(2/stderr, error) 41 # . . push args 42 68/push "write-int: out of space\n"/imm32 43 68/push 2/imm32/stderr 44 # . . call 45 e8/call <a href='101_write.subx.html#L12'>_write</a>/disp32 46 # . . discard args 47 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp 48 # . syscall(exit, 1) 49 bb/copy-to-ebx 1/imm32 50 e8/call <a href='000init.subx.html#L18'>syscall_exit</a>/disp32 51 # never gets here 52 53 test-write-int-single: 54 # - check that write-int writes to first int of 'stream' 55 # setup 56 # . clear-stream(_test-stream) 57 # . . push args 58 68/push <a href='108write.subx.html#L151'>_test-stream</a>/imm32 59 # . . call 60 e8/call <a href='106stream.subx.html#L17'>clear-stream</a>/disp32 61 # . . discard args 62 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp 63 # write-int(_test-stream, "abcd") 64 # . . push args 65 68/push 0x64636261/imm32 66 68/push <a href='108write.subx.html#L151'>_test-stream</a>/imm32 67 # . . call 68 e8/call <a href='202write-int.subx.html#L8'>write-int</a>/disp32 69 # . . discard args 70 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp 71 # check-stream-equal(_test-stream, "abcd", msg) 72 # . . push args 73 68/push "F - test-write-int-single"/imm32 74 68/push "abcd"/imm32 75 68/push <a href='108write.subx.html#L151'>_test-stream</a>/imm32 76 # . . call 77 e8/call <a href='109stream-equal.subx.html#L194'>check-stream-equal</a>/disp32 78 # . . discard args 79 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp 80 # . end 81 c3/return 82 83 test-write-byte-buffered-multiple: 84 # - check that write-int correctly appends multiple writes 85 # setup 86 # . clear-stream(_test-stream) 87 # . . push args 88 68/push <a href='108write.subx.html#L151'>_test-stream</a>/imm32 89 # . . call 90 e8/call <a href='106stream.subx.html#L17'>clear-stream</a>/disp32 91 # . . discard args 92 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 4/imm32 # add to esp 93 # write-int(_test-stream, "abcd") 94 # . . push args 95 68/push 0x64636261/imm32 96 68/push <a href='108write.subx.html#L151'>_test-stream</a>/imm32 97 # . . call 98 e8/call <a href='202write-int.subx.html#L8'>write-int</a>/disp32 99 # . . discard args 100 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp 101 # write-int(_test-stream, "efgh") 102 # . . push args 103 68/push 0x68676665/imm32 104 68/push <a href='108write.subx.html#L151'>_test-stream</a>/imm32 105 # . . call 106 e8/call <a href='202write-int.subx.html#L8'>write-int</a>/disp32 107 # . . discard args 108 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp 109 # check-stream-equal(_test-stream, "abcdefgh", msg) 110 # . . push args 111 68/push "F - test-write-byte-buffered-multiple"/imm32 112 68/push "abcdefgh"/imm32 113 68/push <a href='108write.subx.html#L151'>_test-stream</a>/imm32 114 # . . call 115 e8/call <a href='109stream-equal.subx.html#L194'>check-stream-equal</a>/disp32 116 # . . discard args 117 81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0xc/imm32 # add to esp 118 # . end 119 c3/return 120 121 # . . vim:nowrap:textwidth=0 </pre> </body> </html>


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