msr cpsr_c, #0xc0 | 0x12 // IRQ mode

ldr sp, = TCB_PtrCurrentTask ldr sp, [sp]

sub lr, lr, #4 add sp, sp, #4 stmia sp!, {r0-r12}^

stmia sp! {sp,lr}^

stmia sp! {lr}

sub sp, sp, #68 mrs r1, spsr stmia sp!, {r1}