| Next revision | Previous revision |
| wswan:guide:interrupt_handlers [2024/02/17 13:25] – created asie | wswan:guide:interrupt_handlers [2024/02/18 08:32] (current) – asie |
|---|
| ===== C interrupt handlers ===== | ===== C interrupt handlers ===== |
| |
| For less performance-sensitive interrupts (such as the vertical blank interrupt), it is possible tow rite the relevant handlers using only C. This is done by marking the interrupt function with special attributes: | For less performance-sensitive interrupts (such as the vertical blank interrupt), it is possible to write the relevant handlers using only C. This is done by marking the interrupt function with special attributes: |
| |
| <code C> | <code C> |
| * ''%%__far%%'' - This function is always a "far" call. This is required for interrupt functions - while all functions are "far" calls by default on ''wswan/medium'', this is not true on other subtargets. | * ''%%__far%%'' - This function is always a "far" call. This is required for interrupt functions - while all functions are "far" calls by default on ''wswan/medium'', this is not true on other subtargets. |
| * ''interrupt'' - This function is an interrupt. This ensures it saves/restores all registers and that it uses ''IRET'' to return from the function. | * ''interrupt'' - This function is an interrupt. This ensures it saves/restores all registers and that it uses ''IRET'' to return from the function. |
| * ''assume_ss_data'' - This function can assume that ''SS'' points to the default data segment. This assumption holds true throughout the Wonderful toolchain. However, beware that any assembler code which modifies the location of the stack segment ''SS'' must ensure that an interrupt function with this attribute is never called during its execution. | * ''assume_ss_data'' - This function can assume that ''SS'' points to the default data segment when it is called. This assumption holds true throughout the Wonderful toolchain's default libraries. However, beware that any assembler code which modifies the location of the stack segment ''SS'' must ensure that an interrupt function with this attribute is never called during its execution. |
| |
| ===== Configuring interrupt handlers ===== | ===== Configuring interrupt handlers ===== |
| ws_hwint_disable(HWINT_VBLANK); | ws_hwint_disable(HWINT_VBLANK); |
| </code> | </code> |
| | |
| | <WRAP round important> |
| | Watch out! ''ws_hwint_set_handler'' expects a ''HWINT_IDX'' parameter, while most other ''ws_hwint'' operations - ''enable'', ''disable'', ''ack'' - expect a ''HWINT'' parameter. |
| | |
| | I admit, this is a little confusing. ^^; |
| | </WRAP> |
| | |
| |
