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# write-stream: like write, but write streams rather than strings
== 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
#? Entry: # manual test
#? # write-stream(stdout, _test-stream2)
#? 68/push _test-stream2/imm32
#? 68/push 1/imm32/stdout
#? e8/call write-stream/disp32
#? # syscall(exit, Num-test-failures)
#? 8b/copy 0/mod/indirect 5/rm32/.disp32 . . 3/r32/ebx Num-test-failures/disp32 # copy *Num-test-failures to ebx
#? e8/call syscall_exit/disp32
write-stream: # f: fd or (addr stream byte), s: (addr stream byte)
# . prologue
55/push-ebp
89/copy 3/mod/direct 5/rm32/ebp . . . 4/r32/esp . . # copy esp to ebp
# if (f < 0x08000000) _write-stream(f, s), return # f can't be a user-mode address, so treat it as a kernel file descriptor
81 7/subop/compare 1/mod/*+disp8 5/rm32/ebp . . . . 8/disp8 0x08000000/imm32 # compare *(ebp+8)
73/jump-if-addr>= $write-stream:fake/disp8
# . . push args
ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 0xc/disp8 . # push *(ebp+12)
ff 6/subop/push 1/mod/*+disp8 5/rm32/ebp . . . . 8/disp8 . # push *(ebp+8)
# . . call
e8/call _write-stream/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp
eb/jump $write-stream:end/disp8
$write-stream:fake:
# otherwise, treat 'f' as a stream to append to
# . save registers
50/push-eax
56/push-esi
57/push-edi
# edi = f
8b/copy 1/mod/*+disp8 5/rm32/ebp . . 7/r32/edi 8/disp8 . # copy *(ebp+8) to edi
# esi = s
8b/copy 1/mod/*+disp8 5/rm32/ebp . . 6/r32/esi 0xc/disp8 . # copy *(ebp+12) to esi
# eax = _append-4(&f->data[f->write], &f->data[f->size], &s->data[s->read], &s->data[s->write])
# . . push &s->data[s->write]
8b/copy 0/mod/indirect 6/rm32/esi . . . 0/r32/eax . . # copy *esi to eax
8d/copy-address 1/mod/*+disp8 4/rm32/sib 6/base/esi 0/index/eax . 0/r32/eax 0xc/disp8 . # copy esi+eax+12 to eax
50/push-eax
# . . push &s->data[s->read]
8b/copy 1/mod/*+disp8 6/rm32/esi . . . 0/r32/eax 4/disp8 . # copy *(esi+4) to eax
8d/copy-address 1/mod/*+disp8 4/rm32/sib 6/base/esi 0/index/eax . 0/r32/eax 0xc/disp8 . # copy esi+eax+12 to eax
50/push-eax
# . . push &f->data[f->size]
8b/copy 1/mod/*+disp8 7/rm32/edi . . . 0/r32/eax 8/disp8 . # copy *(edi+8) to eax
8d/copy-address 1/mod/*+disp8 4/rm32/sib 7/base/edi 0/index/eax . 0/r32/eax 0xc/disp8 . # copy edi+eax+12 to eax
50/push-eax
# . . push &f->data[f->write]
8b/copy 0/mod/indirect 7/rm32/edi . . . 0/r32/eax . . # copy *edi to eax
8d/copy-address 1/mod/*+disp8 4/rm32/sib 7/base/edi 0/index/eax . 0/r32/eax 0xc/disp8 . # copy edi+eax+12 to eax
50/push-eax
# . . call
e8/call _append-4/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 0x10/imm32 # add to esp
# f->write += eax
01/add 0/mod/indirect 7/rm32/edi . . . 0/r32/eax . . # add eax to *edi
# s->read += eax
01/add 1/mod/*+disp8 6/rm32/esi . . . 0/r32/eax 4/disp8 . # add eax to *(esi+4)
# . restore registers
5f/pop-to-edi
5e/pop-to-esi
58/pop-to-eax
$write-stream:end:
# . epilogue
89/copy 3/mod/direct 4/rm32/esp . . . 5/r32/ebp . . # copy ebp to esp
5d/pop-to-ebp
c3/return
_write-stream: # fd: int, s: (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
52/push-edx
53/push-ebx
56/push-esi
57/push-edi
# esi = s
8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 6/r32/esi 0xc/disp8 . # copy *(ebp+12) to esi
# edi = s->read
8b/copy 1/mod/*+disp8 6/rm32/esi . . . 7/r32/edi 4/disp8 . # copy *(esi+4) to edi
# edx = s->write
8b/copy 0/mod/indirect 6/rm32/esi . . . 2/r32/edx . . # copy *esi to edx
# syscall(write, fd, &s->data[s->read], s->write - s->read)
# . . fd: ebx
8b/copy 1/mod/*+disp8 5/rm32/ebp . . . 3/r32/ebx 8/disp8 . # copy *(ebp+8) to ebx
# . . data: ecx = &s->data[s->read]
8d/copy-address 1/mod/*+disp8 4/rm32/sib 6/base/esi 7/index/edi . 1/r32/ecx 0xc/disp8 . # copy esi+edi+12 to ecx
# . . size: edx = s->write - s->read
29/subtract 3/mod/direct 2/rm32/edx . . . 7/r32/edi . . # subtract edi from edx
# . . syscall
e8/call syscall_write/disp32
# if (eax < 0) abort
3d/compare-eax-with 0/imm32
0f 8c/jump-if-< $_write-stream:abort/disp32
# s->read += eax
01/add 1/mod/*+disp8 6/rm32/esi . . . 0/r32/eax 4/disp8 . # add eax to *(esi+4)
# . restore registers
5f/pop-to-edi
5e/pop-to-esi
5b/pop-to-ebx
5a/pop-to-edx
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
$_write-stream:abort:
# . _write(2/stderr, error)
# . . push args
68/push "_write-stream: failed to write to file\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
e8/call syscall_exit/disp32
# never gets here
test-write-stream-single:
# 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-stream2)
# . . push args
68/push _test-stream2/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-stream2, "Ab")
# . . push args
68/push "Ab"/imm32
68/push _test-stream2/imm32
# . . call
e8/call write/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp
# write-stream(_test-stream, _test-stream2)
# . . push args
68/push _test-stream2/imm32
68/push _test-stream/imm32
# . . call
e8/call write-stream/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp
# check-stream-equal(_test-stream, "Ab", msg)
# . . push args
68/push "F - test-write-stream-single"/imm32
68/push "Ab"/imm32
68/push _test-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
test-write-stream-appends:
# 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-stream2)
# . . push args
68/push _test-stream2/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-stream2, "C")
# . . push args
68/push "C"/imm32
68/push _test-stream2/imm32
# . . call
e8/call write/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp
# first write
# . write-stream(_test-stream, _test-stream2)
# . . push args
68/push _test-stream2/imm32
68/push _test-stream/imm32
# . . call
e8/call write-stream/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp
# second write
# . write(_test-stream2, "D")
# . . push args
68/push "D"/imm32
68/push _test-stream2/imm32
# . . call
e8/call write/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp
# . write-stream(_test-stream, _test-stream2)
# . . push args
68/push _test-stream2/imm32
68/push _test-stream/imm32
# . . call
e8/call write-stream/disp32
# . . discard args
81 0/subop/add 3/mod/direct 4/rm32/esp . . . . . 8/imm32 # add to esp
# check-stream-equal(_test-stream, "CD", msg)
# . . push args
68/push "F - test-write-stream-appends"/imm32
68/push "CD"/imm32
68/push _test-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
== data
_test-stream2: # (stream byte)
# current write index
4/imm32
# current read index
1/imm32
# size
8/imm32
# data
41/A 42/B 43/C 44/D 00 00 00 00 # 8 bytes
# . . vim:nowrap:textwidth=0
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