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authorKartik Agaram <vc@akkartik.com>2019-07-16 23:34:33 -0700
committerKartik Agaram <vc@akkartik.com>2019-07-16 23:40:25 -0700
commitc2a74205d690862d4df31682aa5bbe992227fda1 (patch)
treeb570f38927e21af0ab05d4864cfd3676bb2b0880 /subx/077slurp.subx
parent70a999aaebbd05873be56b0460e0d4182397cfea (diff)
downloadmu-c2a74205d690862d4df31682aa5bbe992227fda1.tar.gz
5408
Bugfix ten: type error in `convert`. I was calling `rewind-stream` on a
`buffered-file`.

examples/ex1 is now just one nibble off the canonical.

I *have* found one missing feature in the self-hosted translator,
though: dquotes doesn't support newlines in strings, even though the C++
version does. dquotes parses them right, but the value initialized in
the data segment is wrong.
Diffstat (limited to 'subx/077slurp.subx')
-rw-r--r--subx/077slurp.subx161
1 files changed, 161 insertions, 0 deletions
diff --git a/subx/077slurp.subx b/subx/077slurp.subx
new file mode 100644
index 00000000..2bf203da
--- /dev/null
+++ b/subx/077slurp.subx
@@ -0,0 +1,161 @@
+== 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
+
+# read all bytes from 'f' and store them into 's'
+# abort if 's' is too small
+slurp:  # f : (address buffered-file), s : (address stream byte) -> <void>
+    # pseudocode:
+    #   while true
+    #     if (s->write >= s->length) abort
+    #     if (f->read >= f->write) populate stream from file
+    #     if (f->write == 0) break
+    #     AL = f->data[f->read]
+    #     s->data[s->write] = AL
+    #     ++f->read
+    #     ++s->write
+    # . prolog
+    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
+    52/push-EDX
+    56/push-ESI
+    57/push-EDI
+    # ESI = f
+    8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .             .           6/r32/ESI   8/disp8         .                 # copy *(EBP+8) to ESI
+    # ECX = f->read
+    8b/copy                         1/mod/*+disp8   6/rm32/ESI    .           .             .           1/r32/ECX   8/disp8         .                 # copy *(ESI+8) to ECX
+    # EDI = s
+    8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .             .           7/r32/EDI   0xc/disp8       .                 # copy *(EBP+12) to EDI
+    # EDX = s->write
+    8b/copy                         0/mod/indirect  7/rm32/EDI    .           .             .           2/r32/EDX   .               .                 # copy *EDI to EDX
+$slurp:loop:
+    # if (s->write >= s->length) abort
+    3b/compare                      1/mod/*+disp8   7/rm32/EDI    .           .             .           2/r32/EDX   8/disp8         .                 # compare EDX with *(EDI+8)
+    7d/jump-if-greater-or-equal  $slurp:abort/disp8
+    # if (f->read >= f->write) populate stream from file
+    3b/compare                      1/mod/*+disp8   6/rm32/ESI    .           .             .           1/r32/ECX   4/disp8         .                 # compare ECX with *(ESI+4)
+    7c/jump-if-lesser  $slurp:from-stream/disp8
+    # . clear-stream(stream = f+4)
+    # . . push args
+    8d/copy-address                 1/mod/*+disp8   6/rm32/ESI    .           .             .           0/r32/EAX   4/disp8         .                 # copy ESI+4 to EAX
+    50/push-EAX
+    # . . call
+    e8/call  clear-stream/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
+    # . f->read must now be 0; update its cache at ECX
+    31/xor                          3/mod/direct    1/rm32/ECX    .           .             .           1/r32/ECX   .               .                 # clear ECX
+    # . EAX = read(f->fd, stream = f+4)
+    # . . push args
+    50/push-EAX
+    ff          6/subop/push        0/mod/indirect  6/rm32/ESI    .           .             .           .           .               .                 # push *ESI
+    # . . call
+    e8/call  read/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # if (f->write == 0) break
+    # since f->read was initially 0, EAX is the same as f->write
+    # . if (EAX == 0) return true
+    3d/compare-EAX-and  0/imm32
+    74/jump-if-equal  $slurp:end/disp8
+$slurp:from-stream:
+    # AL = f->data[f->read]
+    31/xor                          3/mod/direct    0/rm32/EAX    .           .             .           0/r32/EAX   .               .                 # clear EAX
+    8a/copy-byte                    1/mod/*+disp8   4/rm32/sib    6/base/ESI  1/index/ECX   .           0/r32/AL    0x10/disp8      .                 # copy byte at *(ESI+ECX+16) to AL
+    # s->data[s->write] = AL
+    88/copy-byte                    1/mod/*+disp8   4/rm32/sib    7/base/EDI  2/index/EDX   .           0/r32/AL    0xc/disp8       .                 # copy AL to *(EDI+EDX+12)
+    # ++f->read
+    41/increment-ECX
+    # ++s->write
+    42/increment-EDX
+    eb/jump  $slurp:loop/disp8
+$slurp:end:
+    # save f->read
+    89/copy                         1/mod/*+disp8   6/rm32/ESI    .           .             .           1/r32/ECX   8/disp8         .                 # copy ECX to *(ESI+8)
+    # save s->write
+    89/copy                         0/mod/indirect  7/rm32/EDI    .           .             .           2/r32/EDX   .               .                 # copy EDX to *EDI
+    # . restore registers
+    5f/pop-to-EDI
+    5e/pop-to-ESI
+    5a/pop-to-EDX
+    59/pop-to-ECX
+    58/pop-to-EAX
+    # . epilog
+    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
+    5d/pop-to-EBP
+    c3/return
+
+$slurp:abort:
+    # . _write(2/stderr, error)
+    # . . push args
+    68/push  "slurp: destination too small\n"/imm32
+    68/push  2/imm32/stderr
+    # . . call
+    e8/call  _write/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # . syscall(exit, 1)
+    bb/copy-to-EBX  1/imm32
+    b8/copy-to-EAX  1/imm32/exit
+    cd/syscall  0x80/imm8
+    # never gets here
+
+test-slurp:
+    # setup
+    # . clear-stream(_test-stream)
+    # . . push args
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  clear-stream/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
+    # . clear-stream(_test-buffered-file+4)
+    # . . push args
+    b8/copy-to-EAX  _test-buffered-file/imm32
+    05/add-to-EAX  4/imm32
+    50/push-EAX
+    # . . call
+    e8/call  clear-stream/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
+    # . clear-stream(_test-tmp-stream)
+    # . . push args
+    68/push  _test-tmp-stream/imm32
+    # . . call
+    e8/call  clear-stream/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
+    # write(_test-stream, "ab\ncd")
+    # . . push args
+    68/push  "ab\ncd"/imm32
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  write/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # read a line from _test-stream (buffered by _test-buffered-file) into _test-tmp-stream
+    # . EAX = slurp(_test-buffered-file, _test-tmp-stream)
+    # . . push args
+    68/push  _test-tmp-stream/imm32
+    68/push  _test-buffered-file/imm32
+    # . . call
+    e8/call  slurp/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # check-stream-equal(_test-tmp-stream, "ab\ncd", msg)
+    # . . push args
+    68/push  "F - test-slurp"/imm32
+    68/push  "ab\ncd"/imm32
+    68/push  _test-tmp-stream/imm32
+    # . . call
+    e8/call  check-stream-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
+    # end
+    c3/return
+
+# . . vim:nowrap:textwidth=0