OS_Hardware 0 (changes)
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Hardware Abstraction Layer
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» OS_Hardware 0
OS_Hardware 0
(SWI &7A)
| Entry | |
|---|---|
| R0-R7 | Parameters for hardware routine |
| R8 | 0 |
| R9 | Hardware call number |
| Exit | |
|---|---|
| R0-R3 | Updated by call |
| R4-R9 | Preserved |
Use
This SWI calls a HAL routine. HAL routines internally are ATPCS, so R0-R3 are passed in as a1-a4, and R4-R7 are pushed on to the stack. The a1-a4 on exit from the routine are passed back in R0-R3.
If the HAL routine is not available, an error is returned. Actual HAL routines do not return RISC OS errors – any possible failure will be indicated in a call-specific manner.
Notes
Error &6C1 (Hardware call not available) is returned if the requested call is unknown by this kernel/HAL version, or is a null entry (was (Null implemented offset as in a the ‘MOV pc,lr’ within the HAL ) entry table). Entries which are present but do nothing (i.e. implemented as ‘MOV pc,lr’) do not return an error.
See also
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