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This commit is contained in:
Kartik Agaram 2018-10-28 23:17:56 -07:00
parent 4c37b3e91b
commit 3d94e2db0e
1 changed files with 6 additions and 6 deletions
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12
subx/056write.subx
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@ -2,10 +2,10 @@
# in addition to file descriptors.
#
# Our first dependency-injected and testable primitive. We can pass it either
# a file descriptor or an address to an output stream or ostream. If a file
# descriptor is passed in, we _write to it using the right syscall. If a 'fake
# file descriptor' or ostream is passed in, we append to the output stream.
# This lets us redirect output in tests and check it later.
# a file descriptor or an address to an ostream. If a file descriptor is
# passed in, we _write to it using the right syscall. If a 'fake file descriptor'
# or ostream is passed in, we append to the ostream. This lets us redirect
# output in tests and check it later.
#
# We assume our data segment will never begin at an address shorter than
# 0x08000000, so any smaller arguments are assumed to be real file descriptors.
@ -39,7 +39,7 @@ Test-ostream:
b8/copy-to-EAX 1/imm32
cd/syscall 0x80/imm8
write: # f : fd or (address stream), s : (address array byte) -> <void>
write: # f : fd or (address ostream), s : (address array byte) -> <void>
# prolog
55/push-EBP
89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP
@ -55,7 +55,7 @@ write: # f : fd or (address stream), s : (address array byte) -> <void>
81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP
eb/jump $write:end/disp8
$write:fake:
# otherwise, treat 'f' as a stream to append to
# otherwise, treat 'f' as an ostream to append to
# save registers
50/push-EAX
51/push-ECX