Code (C++)

#ifndef leds_asm_isr_H_
#define leds_asm_isr_H_
extern "C" void ASM_ISR(uint32_t *, uint32_t **, uint32_t **, uint32_t **, uint32_t const *, uint32_t);
#endif /* leds_asm_isr_H_ */ 

Code (C++)

#include "leds_asm_isr.h"

void TCC0_Handler(){ 	// Interrupt Service Routine (ISR) for timer TCC0
ASM_ISR(&iCount, &Strip4_mask_pntr, &Strip4_pntr, &Strip4_base_pntr, &Strip4_Num_LED, CC3_Addr);
} 

Code (C++)

.text
.global ASM_ISR
/* R0 = iCount addr, R1=Strip4_mask_pntr addr, R2 = Strip4_pntr addr, R3 = Strip4_base_pntr addr, Stack = Strip4_Num_LED addr, CC addr */
ASM_ISR:
		cpsid i									@ disable all interrupts
		ldr r4, [r0, #0]						@ get iCounter
		cmp	r4,#0								@ is iCount = 0 ?
		beq	ext									@ exit routine if so
		pop {r4}								@ CC Addr
		pop {r5}								@ Num LEDs Addr
		push {r0}								@ Free r0 | iCount Addr on stack
		ldr r7, = 0x38							@ value for 1 CC PWM LED
		lsl r7, r7, #6							@ Position for CC reg
		ldr r0, [r1, #0]						@ get mask
		ldr r6, [r2, #0]						@ get array element
		and r6, r6, r0							@ test bit
		beq	jmp1								@ if it's 1 jmp
		lsr	r7, r7, #1							@ value for 0 CC PWM LED
jmp1:	str r7, [r4, #0]						@ set new CC val | open regs r4, r6
		lsr r0, r0, #1							@ shift mask bit
		cmp r0, #0								@ Did we empty mask reg
		bne	ext									@ if not we're done
		ldr r4, = 0x80							@ reinitialize mask | open regs r6
		lsl r4, r4, #16							@ 0x00800000
		mov r6, r2								@ get array pointer address
		add r6, #4								@ increment array pntr address
		lsl	r5, r5, #2							@ multi num leds x4 for address calculation
		add r5, r5, r3							@ point to end of array
		cmp r6, r5								@ are we at the last array element
		bne	jmp2								@ if not jmp
		ldr r6, [r3, #0]						@ array pointer back to top of array
jmp2:	str r4, [r1, #0]						@ mask reg to memory
		str r6, [r2, #0]						@ array pointer to memory
		pop {r0}								@ get iCount address
		ldr r4, [r0, #0]						@ get iCount
		sub r4, #1								@ Decrement iCount
		str r4, [r0, #0]						@ iCount to memory
ext:	cpsie i									@ Enable interrupts
		bx    lr								@ Exit
.end