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	Commit message (Expand)	Author	Age	Files	Lines
*	3663 - fix a refcounting bug: '(type)' != 'type'	Kartik K. Agaram	2016-11-10	1	-2/+3
*	3541	Kartik K. Agaram	2016-10-21	1	-3/+1
*	3522	Kartik K. Agaram	2016-10-19	1	-2/+2
*	3381	Kartik K. Agaram	2016-09-17	1	-3/+3
*	3380	Kartik K. Agaram	2016-09-17	1	-9/+9
*	3374	Kartik K. Agaram	2016-09-16	1	-4/+4
*	3309	Kartik K. Agaram	2016-09-09	1	-6/+10
*	3202 - bugfix: 'start-running' and refcounts	Kartik K. Agaram	2016-08-16	1	-0/+1
*	3120	Kartik K. Agaram	2016-07-21	1	-2/+2
*	3079	Kartik K. Agaram	2016-06-29	1	-1/+1
*	3074	Kartik K. Agaram	2016-06-29	1	-1/+2
*	2990	Kartik K. Agaram	2016-05-20	1	-5/+5
*	2931 - be explicit about making copies	Kartik K. Agaram	2016-05-06	1	-2/+2
*	2864 - replace all address:shared with just address	Kartik K. Agaram	2016-04-24	1	-5/+3
*	2862	Kartik K. Agaram	2016-04-24	1	-0/+185

/examples/ex12.subx?h=main&id=2ec6d1e5250e5a36c919354649c3bc3f17261140'>2ec6d1e5 ^

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# Example showing mmap syscall.
# Create a new segment using mmap, save the address, write to it.
#
# To run (from the subx directory):
#   $ subx translate examples/ex12.subx -o examples/ex12
#   $ subx run examples/ex12
# You shouldn't get a segmentation fault.

== 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

    # syscall(mmap, 0x1000)
    bb/copy-to-EBX  Mmap-new-segment/imm32
    b8/copy-to-EAX  0x5a/imm32/mmap
    cd/syscall  0x80/imm8

    # write to *EAX to check that we have access to the newly-allocated segment
    c7/copy                         0/mod/direct    0/rm32/EAX    .           .             .           .           .               0x34/imm32        # copy to *EAX

    # syscall(exit, EAX)
    89/copy                         3/mod/direct    3/rm32/EBX    .           .             .           0/r32/EAX   .               .                 # copy EAX to EBX
    b8/copy-to-EAX  1/imm32/exit
    cd/syscall  0x80/imm8

== data

# various constants used here were found in the Linux sources (search for file mman-common.h)
Mmap-new-segment:  # type mmap_arg_struct
    # addr
    00 00 00 00  # null
    # len
    00 01 00 00  # 0x1000
    # protection flags
    03 00 00 00  # PROT_READ | PROT_WRITE
    # sharing flags
    22 00 00 00  # MAP_PRIVATE | MAP_ANONYMOUS
    # fd
    ff ff ff ff  # -1 since MAP_ANONYMOUS is specified
    # offset
    00 00 00 00  # 0 since MAP_ANONYMOUS is specified

# . . vim:nowrap:textwidth=0