2065 - arrow bugfix - mu - Soul of a tiny new machine. More thorough tests → More comprehensible and rewrite-friendly software → More resilient society.

about summary refs log tree commit diff stats

path: root/html/045space_surround.cc.html

diff options

author	Kartik K. Agaram <vc@akkartik.com>	2015-08-24 13:51:12 -0700
committer	Kartik K. Agaram <vc@akkartik.com>	2015-08-24 13:51:12 -0700
commit	5af1e35808fd09f8cea1969ef937bd42299d30b2 (patch)
tree	c6eb4587427b5134ed5c87a58f0ee6cc2d2819fd /html/045space_surround.cc.html
parent	086acf397feb149a3e466300904d31d5f2684269 (diff)
download	mu-5af1e35808fd09f8cea1969ef937bd42299d30b2.tar.gz

2065 - arrow bugfix

Diffstat (limited to 'html/045space_surround.cc.html')

0 files changed, 0 insertions, 0 deletions

mmit/subx/055stream.subx?h=hlt&id=03c6f1d3858ff0fdb6af6ce4b61bea51f16b33be'>03c6f1d3 ^

71eb22a5 ^

7a583220 ^

33352536 ^

03c6f1d3 ^

33352536 ^

bfcc0f85 ^

33352536 ^

bfcc0f85 ^

33352536 ^

03c6f1d3 ^

33352536 ^

03c6f1d3 ^

33352536 ^

3ac95f6a ^

71eb22a5 ^

33352536 ^

03c6f1d3 ^

2a2a5b1e ^

33352536 ^

6070c23e ^

2a2a5b1e ^

6ecddbaa ^

2a2a5b1e ^

33352536 ^

03c6f1d3 ^

33352536 ^

7a583220 ^

33352536 ^

03c6f1d3 ^

f0705578 ^

71eb22a5 ^

7a583220 ^

33352536 ^

f0705578 ^

33352536 ^

f0705578 ^

33352536 ^

f0705578 ^

33352536 ^

7a583220 ^

33352536 ^

f0705578 ^

1639687b ^

1
2
3

4
5

19
20

34
35

46
47
48

49
50

52
53

58
59

61
62
63

66
67

70
71

73
74

# streams: data structure for operating on arrays in a stateful manner
#
# A stream looks like this:
#   write: int  # index at which writes go
#   read: int  # index that we've read until
#   data: (array byte)  # prefixed by size as usual
#
# some primitives for operating on streams:
#   - clear-stream (clears everything but the data size)
#   - rewind-stream (resets read pointer)

== code
#   instruction                     effective address                                                   register    displacement    immediate
# . op          subop               mod             rm32          base        index         scale       r32
# . 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

clear-stream:  # f: (addr stream byte)
    # . prologue
    55/push-ebp
    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
    # . save registers
    50/push-eax
    51/push-ecx
    # eax = f
    8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .                         0/r32/eax   8/disp8         .                 # copy *(ebp+8) to eax
    # var count/ecx: int = f->size
    8b/copy                         1/mod/*+disp8   0/rm32/eax    .           .             .           1/r32/ecx   8/disp8         .                 # copy *(eax+8) to ecx
    # var max/ecx: (addr byte) = &f->data[f->size]
    8d/copy-address                 1/mod/*+disp8   4/rm32/sib    0/base/eax  1/index/ecx   .           1/r32/ecx   0xc/disp8       .                 # copy eax+ecx+12 to ecx
    # f->write = 0
    c7          0/subop/copy        0/mod/direct    0/rm32/eax    .           .             .           .           .               0/imm32           # copy to *eax
    # f->read = 0
    c7          0/subop/copy        1/mod/*+disp8   0/rm32/eax    .           .             .           .           4/disp8         0/imm32           # copy to *(eax+4)
    # - clear all stream data
    # - this isn't strictly necessary, and it can slow things down *a lot*, but better safe than sorry.
    # var curr/eax: (addr byte) = f->data
    81          0/subop/add         3/mod/direct    0/rm32/eax    .           .             .           .           .               0xc/imm32         # add to eax
$clear-stream:loop:
    # if (curr >= max) break
    39/compare                      3/mod/direct    0/rm32/eax    .           .             .           1/r32/ecx   .               .                 # compare eax with ecx
    73/jump-if-addr>=  $clear-stream:end/disp8
    # *curr = 0
    c6          0/subop/copy-byte   0/mod/direct    0/rm32/eax    .           .             .           .           .               0/imm8            # copy byte to *eax
    # ++curr
    40/increment-eax
    eb/jump  $clear-stream:loop/disp8
$clear-stream:end:
    # . restore registers
    59/pop-to-ecx
    58/pop-to-eax
    # . epilogue
    89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
    5d/pop-to-ebp
    c3/return

rewind-stream:  # f: (addr stream byte)
    # . prologue
    55/push-ebp
    89/copy                         3/mod/direct    5/rm32/ebp    .           .             .           4/r32/esp   .               .                 # copy esp to ebp
    # . save registers
    50/push-eax
    # eax = f
    8b/copy                         1/mod/*+disp8   5/rm32/ebp    .           .                         0/r32/eax   8/disp8         .                 # copy *(ebp+8) to eax
    # f->read = 0
    c7          0/subop/copy        1/mod/*+disp8   0/rm32/eax    .           .             .           .           4/disp8         0/imm32           # copy to *(eax+4)
$rewind-stream:end:
    # . restore registers
    58/pop-to-eax
    # . epilogue
    89/copy                         3/mod/direct    4/rm32/esp    .           .             .           5/r32/ebp   .               .                 # copy ebp to esp
    5d/pop-to-ebp
    c3/return

# . . vim:nowrap:textwidth=0


context:
space:
mode: