OS_Memory 19 Input Function (changes)
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OS SWI Calls
» OS_Memory
» OS_Memory 19
» Input Function
Input Function
| Entry | |
|---|---|
| R9 | R2 from OS_Memory 19 input / R9 output from previous Input Function call |
| R12 | R1 from OS_Memory 19 input |
| SVC32 mode, interrupts enabled | |
| Exit | (32 bit addresses) |
|---|---|
| R0 | Start address of region |
| R1 | Length of region (0 if end of transfer) |
| R2 | Flags: |
| Bit 0: Bounce buffer will be used | |
| Bits 1+: Reserved (zero) | |
| R9 | New R9 for next Input call |
| R12 | Corrupt |
| - | All other registers preserved |
| Exit | (64 bit addresses) |
|---|---|
| R0,R1 | Start address of region |
| R2 | Flags: |
| Bit 0: Bounce buffer will be used | |
| Bits 1+: Reserved (zero) | |
| R3 | Length of region (0 if end of transfer) |
| R9 | New R9 for next Input call |
| R12 | Corrupt |
| - | All other registers preserved |
Use
OS_Memory 19 calls this function to retrieve details about the next region of the buffer involved in the DMA transfer.
Notes
The Bit address 11 returned in R0 should be either a logical or physical address, as indicated by the value you provided in bit 8 of theOS_Memory 19 flags. flags should be used to indicate whether your code is using the 32 bit or 64 bit interface.
The address returned in R0 (or R0/R1) should be either a logical or physical address, as indicated by the value you provided in bit 8 of the OS_Memory 19 flags.
By indicating that a bounce buffer will be used, OS_Memory 19 will avoid performing cache maintenance operations for the indicated region.
See also
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