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https://github.com/italicsjenga/agb.git
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58 lines
1.3 KiB
ArmAsm
58 lines
1.3 KiB
ArmAsm
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@ An interrupt handler that simply acknowledges all interrupts
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.arm
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.global InterruptHandler
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.section .iwram, "ax"
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.align
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InterruptHandler:
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mov r2, #0x04000000 @ interrupt enable register location
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add r2, #0x200
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mov r1, #0
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strh r1, [r2, #8]
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ldrh r1, [r2] @ load 16 bit interrupt enable to r1
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ldrh r3, [r2, #2] @ load 16 bit interrupt request to r3
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and r0, r1, r3 @ interrupts both enabled and requested
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ldr r1, [sp, #20]
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ldr r3, =agb_rs__program_counter
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str r1, [r3]
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@ change to system mode
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mrs r1, cpsr
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orr r1, r1, #0xD
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msr cpsr_c, r1
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@ call the rust interrupt handler with r0 set to the triggered interrupts
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ldr r1, =__RUST_INTERRUPT_HANDLER
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push {lr, r2}
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mov lr, pc
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bx r1
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pop {lr, r2}
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@ change back to interrupt mode
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mrs r1, cpsr
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bic r1, r1, #0xD
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msr cpsr_c, r1
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mov r1, #1
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strh r1, [r2, #8]
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strh r0, [r2, #2] @ store to interrupt request
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ldr r2, =0x03007FF8 @ load bios interrupt request location
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ldrh r1, [r2] @ load bios interrupt requests
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orr r1, r1, r0 @ or with enabled and requested interrupts
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strh r1, [r2] @ acknowlege bios requests
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bx lr @ return to bios
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.pool
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.section .iwram
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.global agb_rs__program_counter
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.balign 4
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agb_rs__program_counter:
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.word 0
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