mu/linux/312copy.subx

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== code
copy-array-object: # src: (addr array T), dest-ah: (addr handle array T)
# . prologue
55/push-ebp
89/<- %ebp 4/r32/esp
#
(copy-array Heap *(ebp+8) *(ebp+0xc))
$copy-array-object:end:
# . epilogue
89/<- %esp 5/r32/ebp
5d/pop-to-ebp
c3/return
# create an independent copy of file src into dest
# there's no way to do this without knowing the filename
copy-file: # src: (addr buffered-file), dest-ah: (addr handle buffered-file), filename: (addr array byte)
# . prologue
55/push-ebp
89/<- %ebp 4/r32/esp
# . save registers
50/push-eax
51/push-ecx
52/push-edx
53/push-ebx
56/push-esi
57/push-edi
# esi = src
8b/-> *(ebp+8) 6/r32/esi
# var n/ecx: int = src->buffer->size + 16
8b/-> *(esi+0xc) 0/r32/eax
05/add-to-eax 0x10/imm32 # buffered-file fields before buffer contents
89/<- %ecx 0/r32/eax
#
(allocate Heap %ecx *(ebp+0xc))
# var dest/edi: (addr buffered-file) = lookup(*dest-ah)
8b/-> *(ebp+0xc) 0/r32/eax
(lookup *eax *(eax+4)) # => eax
89/<- %edi 0/r32/eax
#
(copy-bytes %esi %edi %ecx)
# var offset/ecx: int = lseek(src->fd, 0, SEEK_CUR)
8b/-> *esi 3/r32/ebx
b9/copy-to-ecx 0/imm32/offset
ba/copy-to-edx 1/imm32/whence:SEEK_CUR
(syscall_lseek)
89/<- %ecx 0/r32/eax
# at this point dest is identical to src, including file descriptor. Now
# create an independent copy of the file descriptor
(open-fd *(ebp+0x10) 0) # false => eax
89/<- *edi 0/r32/eax
# replicate offset in the new fd
89/<- %ebx 0/r32/eax # fd
51/push-ecx # offset
ba/copy-to-edx 0/imm32/whence:SEEK_SET
(syscall_lseek)
$copy-file:end:
# . 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/<- %esp 5/r32/ebp
5d/pop-to-ebp
c3/return