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Machine code: Difference between revisions
Simplify Nim example (make it more similar to the original C version)
(Make the Nim version actually work) |
(Simplify Nim example (make it more similar to the original C version)) |
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Line 637:
<lang nim>import posix
▲ MAP_ANONYMOUS {.importc: "MAP_ANONYMOUS", header: "<sys/mman.h>".}: cint
proc test(a, b: cint): cint =
# mov EAX, [ESP+4]
# add EAX, [ESP+8]
# ret
var code = [0x8B'u8, 0x44, 0x24, 0x4, 0x3, 0x44, 0x24, 0x8, 0xC3]
# create an executable buffer
var buf = mmap(nil, sizeof(code), PROT_READ or PROT_WRITE or PROT_EXEC,
MAP_PRIVATE or MAP_ANONYMOUS, -1, 0)
# copy code to the buffer
copyMem(buf, addr code[0], sizeof(code))
# run code
result = cast[proc(a, b: cint): cint {.nimcall.}](buf)(a, b)
# free buffer
discard munmap(buf, sizeof(code))
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