Renesas 70 - Manual (Page 86)

Chapter 5 Detailed Applications
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5.2.3 Writing Non-kernel(OS-independent) Interrupt Handler
1. For the symbol indicating the interrupt handler start address, make the external declaration
(public declaration).
2. Make sure that the registers used in a handler are saved at the entry and are restored after
use.
3. Be sure to end the handler by REIT instruction.
4. No service calls can be issued from a non-kernel(an OS-independent) interrupt handler.
NOTE: If this restriction is not observed, the software may malfunction.
5. If you want multiple interrupts to be enabled in a non-kernel(an OS-independent) interrupt
handler, always make sure that the non-kernel(OS-independent) interrupt handler is as-
signed a priority level higher than other non-kernel(OS-dependent) interrupt handlers.
54
.GLB inthand ----- (1)
inthand:
; Registers used are saved to a stack ----- (2)
; interrupt process
; Registers used are restored
----- (2)
REIT ----- (3)
Figure 5.9 Example of Non-kernel(OS-independent) Interrupt Handler of Specific Level
54 If you want the non-kernel(OS-independent) interrupt handler to be assigned a priority level lower than kernel(OS-dependent) interrupt
handlers, change the description of the non-kernel(OS-independent) interrupt handler to that of the kernel (OS-dependent) interrupt handler.