Force SYS68K/CPU-30 R4, Техническое справочное руководство

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FGA Boot Software SYS68K/CPU-30 R4 Technical Reference Manual
Page 192
11
The FGA Boot Utility Interface
The FGA Boot Software provides several utility functions which can be
called from within a user’s application. This section describes all
additional functions not listed in the FGA-002 User’s Manual.
The interface expects C-like calling conventions, thus all parameters
have to be placed as long values on the supervisor stack. The first
parameter (which must be pushed onto the stack as last one), must
contain the number of the requested function, the rest of the parameters
depends on the specified function.
NOTE: The utility interface must be called in supervisor mode. It will
NOT install its own stack but will use the application’s stack!
Stack frame:
To do a utility call, proceed as follows:
- retrieve the entry address from location
0008
16
- load function number and specific arguments onto the stack
- call the FGA-Boot Utility Interface in supervisor mode (JSR)
- retrieve return code from the interface (register D0)
- clean up stack (arguments are still on the stack)
A7
⇒
return address
+4 function number
+8 first fct. argument
+12 second fct. argument
..... ................................
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