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General AMX Operation
2.4 Starting AMX
An AMX operating system consists of AMX, the subset of its managers which you
choose to use and your complement of application programs. All of these modules are
connected together to form the AMX operating system as described in the AMX Tool
Guide.
Before launching AMX, you must establish the required operating mode for the particular
target processor you are using. AMX 86 operates only in the 8086 real mode.
AMX uses the Medium or Large segmentation model in which multiple code segments
and one or more read/write data segments are provided. AMX makes no assumption
about the manner in which these segments correlate to physical memory.
AMX is launched with a launch parameter defining the nature of the launch. The launch
parameter is a 16-bit unsigned integer in which each bit defines a particular launch
characteristic. Bit mask mnemonics AMLPxx are defined in include files AMX831SD.H and
AMX831SD.DEF.
Bit Value Launch parameter
0 0Launch is permanent
AMLPTMP Launch is temporary
1 0Vector Table is not alterable (in ROM or not accessible)
AMLPVA Vector Table is alterable (in RAM and accessible)
2 0Interrupts disabled during launch
AMLPIE Interrupts enabled during launch
AMX is always launched from your main program (or startup module) by calling AMX
procedure ajentr from C or AAENTR from assembly language.
Your AMX operating system can be launched in two ways: permanently or temporarily.
The type of launch is determined by bit 0 of the launch parameter.
Bit 1 of the launch parameter indicates whether or not AMX will be permitted to alter the
processor vector table. For most applications, the vector table is in RAM and therefore
alterable.
AMX disables the interrupt system at the time you launch AMX. Unless bit 2 of your
launch parameter indicates otherwise, interrupts will remain disabled during the startup
process while AMX initializes its internal parameters and calls each of your Restart
Procedures.