git.mutantstargoat.com Git - rpikern/blob - src/intrasm.s

   1         .code 32
   2
   3 @       .section .vect,"a"
   4 @       .extern startup
   5 @intr_vector:
   6 @       b startup
   7 @       b intr_entry_undef
   8 @       b intr_entry_swi
   9 @       b intr_entry_iabort
  10 @       b intr_entry_dabort
  11 @       b intr_entry_irq
  12 @
  13 @       @ FIQ entry point used for timer interrupts
  14 @intr_entry_fiq:
  15 @       ldr r9, =num_ticks
  16 @       ldr r8, [r9]
  17 @       add r8, #1
  18 @       str r8, [r9]
  19 @       subs pc, lr, #4
  20 @       .align 8
  21 @       .ascii "xyzzy"
  22 @
  23         .text
  24
  25         .global intr_entry_nop
  26         .global intr_entry_undef
  27         .global intr_entry_swi
  28         .global intr_entry_iabort
  29         .global intr_entry_dabort
  30         .global intr_entry_irq
  31         .global intr_entry_fiq
  32
  33 intr_entry_undef:
  34 intr_entry_swi:
  35 intr_entry_iabort:
  36 intr_entry_dabort:
  37 intr_entry_nop:
  38         subs pc, lr, #4
  39
  40 intr_entry_irq:
  41         ldr sp, =_stacktop      @ HACK
  42
  43         stmfd sp!, {r0, r1}
  44
  45         mov r0, #'.'
  46         .extern ser_putchar
  47         bl ser_putchar
  48
  49         ldr r1, =num_ticks
  50         ldr r0, [r1]
  51         add r0, #1
  52         str r0, [r1]
  53
  54         @ setup next interrupt
  55         ldr r1, =#0x3f003004    @ low counter in rpi2 TODO use rpi_iobase
  56         ldr r0, [r1]
  57         add r0, #4000           @ 1Mhz / 250hz = 4k counts
  58         ldr r1, =#0x3f003010    @ compare 1 reg
  59         str r0, [r1]
  60
  61         @ clear interrupt
  62         ldr r1, =#0x3f003000
  63         mov r0, #2      @ set bit 1 to clear interrupt from C1
  64         str r0, [r1]
  65
  66         ldmfd sp!, {r0, r1}
  67         subs pc, lr, #4
  68
  69 intr_entry_fiq:
  70         ldr r9, =num_ticks
  71         ldr r8, [r9]
  72         add r8, #1
  73         str r8, [r9]
  74         subs pc, lr, #4
  75
  76 @ vi:set ft=armasm: