Mu - linux/202write-int.subx

From 3350c34a74844e21ea69077e01efff3bae64bdcd Mon Sep 17 00:00:00 2001 From: Kartik Agaram Date: Tue, 23 Mar 2021 17:31:08 -0700 Subject: . --- html/linux/202write-int.subx.html | 185 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 185 insertions(+) create mode 100644 html/linux/202write-int.subx.html (limited to 'html/linux/202write-int.subx.html') diff --git a/html/linux/202write-int.subx.html b/html/linux/202write-int.subx.html new file mode 100644 index 00000000..11886b06 --- /dev/null +++ b/html/linux/202write-int.subx.html @@ -0,0 +1,185 @@ + + + + +Mu - linux/202write-int.subx + + + + + + + + + + +https://github.com/akkartik/mu/blob/main/linux/202write-int.subx +

+  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  _write/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  syscall_exit/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  _test-stream/imm32
+ 59     # . . call
+ 60     e8/call  clear-stream/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  _test-stream/imm32
+ 67     # . . call
+ 68     e8/call  write-int/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  _test-stream/imm32
+ 76     # . . call
+ 77     e8/call  check-stream-equal/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  _test-stream/imm32
+ 89     # . . call
+ 90     e8/call  clear-stream/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  _test-stream/imm32
+ 97     # . . call
+ 98     e8/call  write-int/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  _test-stream/imm32
+105     # . . call
+106     e8/call  write-int/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  _test-stream/imm32
+114     # . . call
+115     e8/call  check-stream-equal/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
+

+ + + -- cgit 1.4.1-2-gfad0