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AMX 68000 Target Guide
Conforming ISP Declarations
The Target Parameter File must include a definition of an ISP root for each conforming
Interrupt Service Procedure (ISP) which you intend to use in your application. The ISP
root definition is provided using one of the following directives. The ISP root is declared
using ...ISPC if its Interrupt Handler is coded in C or ...ISPA if its Interrupt Handler is
coded in assembly language.
...ISPC ISPROOT,HANDLER,VNUM,PARAM,PARTYPE
...ISPA ISPROOT,HANDLER,VNUM,PARAM,PARTYPE
ISPROOT
Name of the ISP root entry point
HANDLER Name of the public device Interrupt Handler
VNUM Interrupt vector number assigned to the device
PARAM Interrupt Handler parameter
PARTYPE Parameter PARAM type
If your Interrupt Handler does not require a parameter, leave field PARAM blank (empty)
and set PARTYPE to 0.
If your Interrupt Handler requires a numeric parameter, set PARAM to the 32-bit signed or
unsigned value and set PARTYPE to 0. The numeric value must be expressed in a form
acceptable to your assembler.
If your Interrupt Handler requires a pointer to a public variable as a parameter, let PARAM
be the name of that variable and set PARTYPE to 1.
VNUM defines the interrupt vector number which you have assigned to the device. VNUM is
25 to 31 or 64 to 255. Note that all other vector numbers in the range 0 to 255 are
reserved by Motorola.
If VNUM is 0 to 255, AMX will automatically install the pointer to the ISP root ISPROOT
into vector number VNUM in the AMX Vector Table when AMX is launched. The pointer
will be installed by AMX before any application Restart Procedures execute.
Consequently, you must ensure that interrupts from the device are not possible at the time
AMX is launched.
If
VNUM is -1, you must provide a Restart Procedure or task which installs the pointer to
the ISP root ISPROOT into the AMX Vector Table using AMX procedure cjksivtwr or
cjksivtx.
Note
Parameter VNUM cannot be adjusted using the AMX
Configuration Builder. This parameter is provided for
compatibility with other AMX implementations.