From 3ff2fe607c2cb5690d201d3b83ddcc957e949b7a Mon Sep 17 00:00:00 2001 From: Kartik Agaram Date: Tue, 9 Nov 2021 09:23:31 -0800 Subject: . --- html/115write-byte.subx.html | 183 ++++++++++++++++++++++++------------------- 1 file changed, 104 insertions(+), 79 deletions(-) (limited to 'html/115write-byte.subx.html') diff --git a/html/115write-byte.subx.html b/html/115write-byte.subx.html index 79ffa2c9..623dec48 100644 --- a/html/115write-byte.subx.html +++ b/html/115write-byte.subx.html @@ -58,85 +58,110 @@ if ('onhashchange' in window) { https://github.com/akkartik/mu/blob/main/115write-byte.subx
- 1 # Write a single byte to a stream.
- 2 #
- 3 # We need to do this in machine code because streams need to be opaque types,
- 4 # and we don't yet support opaque types in Mu.
- 5 
- 6 == code
- 7 #   instruction                     effective address                                                   register    displacement    immediate
- 8 # . op          subop               mod             rm32          base        index         scale       r32
- 9 # . 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
-10 
-11 # Write lower byte of 'n' to 'f'.
-12 append-byte:  # f: (addr stream byte), n: int
-13     # . prologue
-14     55/push-ebp
-15     89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
-16     # . save registers
-17     50/push-eax
-18     51/push-ecx
-19     57/push-edi
-20     # edi = f
-21     8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           7/r32/edi   8/disp8         .                 # copy *(ebp+8) to edi
-22     # ecx = f->write
-23     8b/copy                         0/mod/indirect  7/rm32/edi    .           .             .           1/r32/ecx   .               .                 # copy *edi to ecx
-24     # if (f->write >= f->size) abort
-25     3b/compare                      1/mod/*+disp8   7/rm32/edi    .           .             .           1/r32/ecx   8/disp8         .                 # compare ecx with *(edi+8)
-26     7d/jump-if->=  $append-byte:abort/disp8
-27 $append-byte:to-stream:
-28     # write to stream
-29     # f->data[f->write] = LSB(n)
-30     31/xor                          3/mod/direct    0/rm32/eax    .           .             .           0/r32/eax   .               .                 # clear eax
-31     8a/copy-byte                    1/mod/*+disp8   5/rm32/ebp    .           .             .           0/r32/AL    0xc/disp8       .                 # copy byte at *(ebp+12) to AL
-32     88/copy-byte                    1/mod/*+disp8   4/rm32/sib    7/base/edi  1/index/ecx   .           0/r32/AL    0xc/disp8       .                 # copy AL to *(edi+ecx+12)
-33     # ++f->write
-34     ff          0/subop/increment   0/mod/indirect  7/rm32/edi    .           .             .           .           .               .                 # increment *edi
-35 $append-byte:end:
-36     # . restore registers
-37     5f/pop-to-edi
-38     59/pop-to-ecx
-39     58/pop-to-eax
-40     # . epilogue
-41     89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
-42     5d/pop-to-ebp
-43     c3/return
-44 
-45 $append-byte:abort:
-46     (abort "append-byte: out of space")
-47     # never gets here
-48 
-49 test-append-byte-single:
-50     # - check that append-byte writes to first byte of 'file'
-51     # setup
-52     # . clear-stream(_test-stream)
-53     # . . push args
-54     68/push  _test-stream/imm32
-55     # . . call
-56     e8/call  clear-stream/disp32
-57     # . . discard args
-58     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
-59     # append-byte(_test-stream, 'A')
-60     # . . push args
-61     68/push  0x41/imm32
-62     68/push  _test-stream/imm32
-63     # . . call
-64     e8/call  append-byte/disp32
-65     # . . discard args
-66     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
-67     # check-stream-equal(_test-stream, "A", msg)
-68     # . . push args
-69     68/push  "F - test-append-byte-single"/imm32
-70     68/push  "A"/imm32
-71     68/push  _test-stream/imm32
-72     # . . call
-73     e8/call  check-stream-equal/disp32
-74     # . . discard args
-75     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
-76     # . end
-77     c3/return
-78 
-79 # . . vim:nowrap:textwidth=0
+  1 # Write a single byte to a stream.
+  2 #
+  3 # We need to do this in machine code because streams need to be opaque types,
+  4 # and we don't yet support opaque types in Mu.
+  5 
+  6 == code
+  7 #   instruction                     effective address                                                   register    displacement    immediate
+  8 # . op          subop               mod             rm32          base        index         scale       r32
+  9 # . 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
+ 10 
+ 11 # Write lower byte of 'n' to 'f'.
+ 12 append-byte:  # f: (addr stream byte), n: int
+ 13     # . prologue
+ 14     55/push-ebp
+ 15     89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+ 16     # . save registers
+ 17     50/push-eax
+ 18     51/push-ecx
+ 19     57/push-edi
+ 20     # edi = f
+ 21     8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           7/r32/edi   8/disp8         .                 # copy *(ebp+8) to edi
+ 22     # ecx = f->write
+ 23     8b/copy                         0/mod/indirect  7/rm32/edi    .           .             .           1/r32/ecx   .               .                 # copy *edi to ecx
+ 24     # if (f->write >= f->size) abort
+ 25     3b/compare                      1/mod/*+disp8   7/rm32/edi    .           .             .           1/r32/ecx   8/disp8         .                 # compare ecx with *(edi+8)
+ 26     7d/jump-if->=  $append-byte:abort/disp8
+ 27 $append-byte:to-stream:
+ 28     # write to stream
+ 29     # f->data[f->write] = LSB(n)
+ 30     31/xor                          3/mod/direct    0/rm32/eax    .           .             .           0/r32/eax   .               .                 # clear eax
+ 31     8a/copy-byte                    1/mod/*+disp8   5/rm32/ebp    .           .             .           0/r32/AL    0xc/disp8       .                 # copy byte at *(ebp+12) to AL
+ 32     88/copy-byte                    1/mod/*+disp8   4/rm32/sib    7/base/edi  1/index/ecx   .           0/r32/AL    0xc/disp8       .                 # copy AL to *(edi+ecx+12)
+ 33     # ++f->write
+ 34     ff          0/subop/increment   0/mod/indirect  7/rm32/edi    .           .             .           .           .               .                 # increment *edi
+ 35 $append-byte:end:
+ 36     # . restore registers
+ 37     5f/pop-to-edi
+ 38     59/pop-to-ecx
+ 39     58/pop-to-eax
+ 40     # . epilogue
+ 41     89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
+ 42     5d/pop-to-ebp
+ 43     c3/return
+ 44 
+ 45 $append-byte:abort:
+ 46     (abort "append-byte: out of space")
+ 47     # never gets here
+ 48 
+ 49 test-append-byte-single:
+ 50     # - check that append-byte writes to first byte of 'file'
+ 51     # setup
+ 52     # . clear-stream(_test-stream)
+ 53     # . . push args
+ 54     68/push  _test-stream/imm32
+ 55     # . . call
+ 56     e8/call  clear-stream/disp32
+ 57     # . . discard args
+ 58     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               4/imm32           # add to esp
+ 59     # append-byte(_test-stream, 'A')
+ 60     # . . push args
+ 61     68/push  0x41/imm32
+ 62     68/push  _test-stream/imm32
+ 63     # . . call
+ 64     e8/call  append-byte/disp32
+ 65     # . . discard args
+ 66     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               8/imm32           # add to esp
+ 67     # check-stream-equal(_test-stream, "A", msg)
+ 68     # . . push args
+ 69     68/push  "F - test-append-byte-single"/imm32
+ 70     68/push  "A"/imm32
+ 71     68/push  _test-stream/imm32
+ 72     # . . call
+ 73     e8/call  check-stream-equal/disp32
+ 74     # . . discard args
+ 75     81          0/subop/add         3/mod/direct    4/rm32/esp    .           .             .           .           .               0xc/imm32         # add to esp
+ 76     # . end
+ 77     c3/return
+ 78 
+ 79 undo-append-byte:  # f: (addr stream byte)
+ 80     # . prologue
+ 81     55/push-ebp
+ 82     89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
+ 83     # . save registers
+ 84     50/push-eax
+ 85     # eax = f
+ 86     8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .             .           0/r32/eax   8/disp8         .                 # copy *(ebp+8) to eax
+ 87     # if (f->write <= 0) abort
+ 88     81          7/subop/compare     0/mod/indirect  0/rm32/eax    .           .             .           .           .               0/imm32           # compare *eax
+ 89     7e/jump-if-<=  $undo-append-byte:abort/disp8
+ 90     # --f->write
+ 91     ff          1/subop/decrement   0/mod/indirect  0/rm32/eax    .           .             .           .           .               .                 # decrement *eax
+ 92 $undo-append-byte:end:
+ 93     # . restore registers
+ 94     58/pop-to-eax
+ 95     # . epilogue
+ 96     89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
+ 97     5d/pop-to-ebp
+ 98     c3/return
+ 99 
+100 $undo-append-byte:abort:
+101     (abort "undo-append-byte: empty stream")
+102     # never gets here
+103 
+104 # . . vim:nowrap:textwidth=0
-- cgit 1.4.1-2-gfad0