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< title > Mu - 102keyboard.subx< / title >
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< meta name = "plugin-version" content = "vim8.1_v2" >
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.SpecialChar { color: #d70000; }
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.subxComment { color: #005faf; }
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.subxS1Comment { color: #0000af; }
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< a href = 'https://github.com/akkartik/mu/blob/main/102keyboard.subx' > https://github.com/akkartik/mu/blob/main/102keyboard.subx< / a >
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< pre id = 'vimCodeElement' >
< span id = "L1" class = "LineNr" > 1 < / span > < span class = "subxComment" > # check keyboard for a key< / span >
< span id = "L2" class = "LineNr" > 2 < / span > < span class = "subxComment" > # return 0 on no keypress or unrecognized key< / span >
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< span id = "L3" class = "LineNr" > 3 < / span > < span class = "subxComment" > #< / span >
< span id = "L4" class = "LineNr" > 4 < / span > < span class = "subxComment" > # We need to do this in machine code because Mu doesn't have global variables< / span >
< span id = "L5" class = "LineNr" > 5 < / span > < span class = "subxComment" > # yet (for the keyboard buffer).< / span >
< span id = "L6" class = "LineNr" > 6 < / span >
< span id = "L7" class = "LineNr" > 7 < / span > == code
< span id = "L8" class = "LineNr" > 8 < / span >
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< span id = "L9" class = "LineNr" > 9 < / span > < span class = "subxComment" > # Most keys correspond to their ASCII/Unicode values.< / span >
< span id = "L10" class = "LineNr" > 10 < / span > < span class = "subxComment" > # TODO: Support for international keyboards and multi-byte Unicode.< / span >
< span id = "L11" class = "LineNr" > 11 < / span > < span class = "subxComment" > #< / span >
< span id = "L12" class = "LineNr" > 12 < / span > < span class = "subxComment" > # However there are some exceptions that have no assigned place in Unicode< / span >
< span id = "L13" class = "LineNr" > 13 < / span > < span class = "subxComment" > # (and with good reason):< / span >
< span id = "L14" class = "LineNr" > 14 < / span > < span class = "subxComment" > # 0x80 = left arrow ←< / span >
< span id = "L15" class = "LineNr" > 15 < / span > < span class = "subxComment" > # 0x81 = down arrow ↓< / span >
< span id = "L16" class = "LineNr" > 16 < / span > < span class = "subxComment" > # 0x82 = up arrow ↑< / span >
< span id = "L17" class = "LineNr" > 17 < / span > < span class = "subxComment" > # 0x83 = right arrow →< / span >
< span id = "L18" class = "LineNr" > 18 < / span > < span class = "subxComment" > # These code points are not used by Unicode and their semantics are agreed to< / span >
< span id = "L19" class = "LineNr" > 19 < / span > < span class = "subxComment" > # be context-sensitive: < a href = "https://en.wikipedia.org/wiki/C0_and_C1_control_codes#C1_controls." > https://en.wikipedia.org/wiki/C0_and_C1_control_codes#C1_controls.< / a > < / span >
< span id = "L20" class = "LineNr" > 20 < / span > < span class = "subxComment" > # Mu cannibalizes them in yet another non-standard way.< / span >
< span id = "L21" class = "LineNr" > 21 < / span > < span class = "subxFunction" > read-key< / span > : < span class = "subxComment" > # kbd: (addr keyboard) -> result/eax: byte< / span >
< span id = "L22" class = "LineNr" > 22 < / span > < span class = "subxS1Comment" > # . prologue< / span >
< span id = "L23" class = "LineNr" > 23 < / span > 55/push-ebp
< span id = "L24" class = "LineNr" > 24 < / span > 89/< - %ebp 4/r32/esp
< span id = "L25" class = "LineNr" > 25 < / span > < span class = "subxS1Comment" > # . save registers< / span >
< span id = "L26" class = "LineNr" > 26 < / span > 51/push-ecx
< span id = "L27" class = "LineNr" > 27 < / span > < span class = "subxComment" > # result = 0< / span >
< span id = "L28" class = "LineNr" > 28 < / span > b8/copy-to-eax 0/imm32
< span id = "L29" class = "LineNr" > 29 < / span > < span class = "subxComment" > # ecx = keyboard< / span >
< span id = "L30" class = "LineNr" > 30 < / span > 8b/-> *(ebp+8) 1/r32/ecx
< span id = "L31" class = "LineNr" > 31 < / span > 81 7/subop/compare %ecx 0/imm32
< span id = "L32" class = "LineNr" > 32 < / span > {
< span id = "L33" class = "LineNr" > 33 < / span > 75/jump-if-!= < span class = "Constant" > break< / span > /disp8
< span id = "L34" class = "LineNr" > 34 < / span > < span class = "subxComment" > # var buffer-byte-addr/ecx: (addr byte)< / span >
< span id = "L35" class = "LineNr" > 35 < / span > 8b/-> *< span class = "SpecialChar" > Keyboard-buffer< / span > :read 1/r32/CL
< span id = "L36" class = "LineNr" > 36 < / span > 81 0/subop/add %ecx < span class = "SpecialChar" > Keyboard-buffer< / span > :data/imm32
< span id = "L37" class = "LineNr" > 37 < / span > < span class = "subxComment" > # var next-key/eax: byte = *buffer-byte-addr< / span >
< span id = "L38" class = "LineNr" > 38 < / span > 8a/byte-> *ecx 0/r32/AL
< span id = "L39" class = "LineNr" > 39 < / span > < span class = "subxComment" > # if (next-key != 0) lock and remove from keyboard buffer< / span >
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< span id = "L40" class = "LineNr" > 40 < / span > 3d/compare-eax-with 0/imm32
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< span id = "L41" class = "LineNr" > 41 < / span > {
< span id = "L42" class = "LineNr" > 42 < / span > 74/jump-if-= < span class = "Constant" > break< / span > /disp8
< span id = "L43" class = "LineNr" > 43 < / span > fa/disable-interrupts
< span id = "L44" class = "LineNr" > 44 < / span > c6 0/subop/copy-byte *ecx 0/imm8
< span id = "L45" class = "LineNr" > 45 < / span > ff 0/subop/increment *< span class = "SpecialChar" > Keyboard-buffer< / span > :read
< span id = "L46" class = "LineNr" > 46 < / span > 81 4/subop/and *< span class = "SpecialChar" > Keyboard-buffer< / span > :read 0x0f/imm32
< span id = "L47" class = "LineNr" > 47 < / span > fb/enable-interrupts
< span id = "L48" class = "LineNr" > 48 < / span > }
< span id = "L49" class = "LineNr" > 49 < / span > < span class = "subxComment" > # return< / span >
< span id = "L50" class = "LineNr" > 50 < / span > eb $read-key:end/disp8
< span id = "L51" class = "LineNr" > 51 < / span > }
< span id = "L52" class = "LineNr" > 52 < / span > < span class = "subxComment" > # TODO: fake keyboard< / span >
< span id = "L53" class = "LineNr" > 53 < / span > < span class = "Constant" > $read-key:end< / span > :
< span id = "L54" class = "LineNr" > 54 < / span > < span class = "subxS1Comment" > # . restore registers< / span >
< span id = "L55" class = "LineNr" > 55 < / span > 59/pop-to-ecx
< span id = "L56" class = "LineNr" > 56 < / span > < span class = "subxS1Comment" > # . epilogue< / span >
< span id = "L57" class = "LineNr" > 57 < / span > 89/< - %esp 5/r32/ebp
< span id = "L58" class = "LineNr" > 58 < / span > 5d/pop-to-ebp
< span id = "L59" class = "LineNr" > 59 < / span > c3/return
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< / pre >
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