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| 208 | * Function Name : IRQHandler |
208 | * Function Name : IRQHandler |
| 209 | * Description : This function called when IRQ exception is entered. |
209 | * Description : This function called when IRQ exception is entered. |
| 210 | * Input : none |
210 | * Input : none |
| 211 | * Output : none |
211 | * Output : none |
| 212 | *******************************************************************************/ |
212 | *******************************************************************************/ |
| 213 | - | ||
| 214 | IRQHandler: |
213 | IRQHandler: |
| 215 | SUB lr, lr, #4 /* Update the link register */ |
214 | SUB lr, lr, #4 /* Update the link register */ |
| 216 | SaveContext r0, r12 /* Save the workspace plus the current */ |
215 | SaveContext r0, r12 /* Save the workspace plus the current */ |
| 217 | /* return address lr_irq and spsr_irq */ |
216 | /* return address lr_irq and spsr_irq */ |
| 218 | LDR r0, =VectorAddress |
217 | LDR r0, =VectorAddress |
| 219 | LDR r0, [r0] /* Read the routine address */ |
218 | LDR r0, [r0] /* Read the routine address of VIC0 */ |
| 220 | LDR r1, =VectorAddressDaisy |
219 | LDR r1, =VectorAddressDaisy |
| 221 | LDR r1, [r1] |
220 | LDR r1, [r1] /* Read the routine address of VIC1 */ |
| 222 | /* Padding between the acknowledge and re-enable of interrupts */ |
221 | /* Padding between the acknowledge and re-enable of interrupts */ |
| 223 | /* For more details, please refer to the following URL */ |
222 | /* For more details, please refer to the following URL */ |
| 224 | /* http://www.arm.com/support/faqip/3682.html */ |
223 | /* http://www.arm.com/support/faqip/3682.html */ |
| 225 | NOP |
224 | NOP |
| 226 | NOP |
225 | NOP |
| 227 | MSR cpsr_c, #Mode_SYS /* Switch to SYS mode and enable IRQ */ |
226 | # MSR cpsr_c, #Mode_SYS /* Switch to SYS mode and enable IRQ */ |
| 228 | STMFD sp!, {lr} /* Save the link register. */ |
227 | # STMFD sp!, {lr} /* Save the link register. */ |
| 229 | LDR lr, =ReturnAddress /* Read the return address. */ |
228 | LDR lr, =ReturnAddress /* Read the return address. */ |
| - | 229 | CMP r0, #0 /* Is VIC0 VAR zero? */ |
|
| - | 230 | BEQ SkipVic0 |
|
| 230 | MOV pc, r0 /* Branch to the IRQ handler. */ |
231 | BX r0 /* Branch to the IRQ handler. */ |
| - | 232 | SkipVic0: |
|
| - | 233 | CMP r1, #0 /* Is VIC1 VAR zero? */ |
|
| - | 234 | BEQ ReturnAddress |
|
| - | 235 | BX r1 /* Branch to the IRQ handler. */ |
|
| 231 | ReturnAddress: |
236 | ReturnAddress: |
| 232 | LDMFD sp!, {lr} /* Restore the link register. */ |
237 | # LDMFD sp!, {lr} /* Restore the link register. */ |
| 233 | MSR cpsr_c, #Mode_IRQ|I_BIT|F_BIT /* Switch to IRQ mode and disable IRQ */ |
238 | # MSR cpsr_c, #Mode_IRQ|I_BIT /* Switch to IRQ mode and disable IRQ */ |
| 234 | LDR r0, =VectorAddress /* Write to the VectorAddress to clear the */ |
239 | LDR r0, =VectorAddress /* Write to the VectorAddress to clear the */ |
| 235 | STR r0, [r0] /* respective interrupt in the internal interrupt */ |
240 | STR r0, [r0] /* respective interrupt in the internal interrupt */ |
| 236 | LDR r1, =VectorAddressDaisy /* Write to the VectorAddressDaisy to clear the */ |
241 | LDR r1, =VectorAddressDaisy /* Write to the VectorAddressDaisy to clear the */ |
| 237 | STR r1, [r1] /* respective interrupt in the internal interrupt */ |
242 | STR r1, [r1] /* respective interrupt in the internal interrupt */ |
| 238 | RestoreContext r0, r12 /* Restore the context and return to the program execution. */ |
243 | RestoreContext r0, r12 /* Restore the context and return to the program execution. */ |