fighting with interrupt vectors

[rpikern] / src / intrasm.s

diff --git a/src/intrasm.s b/src/intrasm.s
index 4ef2cd0..874520f 100644 (file)
--- a/src/intrasm.s
+++ b/src/intrasm.s
@@ -1,28 +1,76 @@
        .code 32
 
-       .section .vect
-       .extern startup
-intr_vector:
-       b startup
-       b intr_entry_undef
-       b intr_entry_swi
-       b intr_entry_iabort
-       b intr_entry_dabort
-       b intr_entry_irq
-
-       @ FIQ entry point used for timer interrupts
-       .extern num_ticks
-intr_entry_fiq:
-       ldr r9, =num_ticks
-       ldr r8, [r9]
-       add r8, #1
-       str r8, [r9]
-       subs pc, lr, #4
-
+@      .section .vect,"a"
+@      .extern startup
+@intr_vector:
+@      b startup
+@      b intr_entry_undef
+@      b intr_entry_swi
+@      b intr_entry_iabort
+@      b intr_entry_dabort
+@      b intr_entry_irq
+@
+@      @ FIQ entry point used for timer interrupts
+@intr_entry_fiq:
+@      ldr r9, =num_ticks
+@      ldr r8, [r9]
+@      add r8, #1
+@      str r8, [r9]
+@      subs pc, lr, #4
+@      .align 8
+@      .ascii "xyzzy"
+@
        .text
+
+       .global intr_entry_nop
+       .global intr_entry_undef
+       .global intr_entry_swi
+       .global intr_entry_iabort
+       .global intr_entry_dabort
+       .global intr_entry_irq
+       .global intr_entry_fiq
+
 intr_entry_undef:
 intr_entry_swi:
 intr_entry_iabort:
 intr_entry_dabort:
+intr_entry_nop:
+       subs pc, lr, #4
+
 intr_entry_irq:
+       ldr sp, =_stacktop      @ HACK
+
+       stmfd sp!, {r0, r1}
+
+       mov r0, #'.'
+       .extern ser_putchar
+       bl ser_putchar
+
+       ldr r1, =num_ticks
+       ldr r0, [r1]
+       add r0, #1
+       str r0, [r1]
+
+       @ setup next interrupt
+       ldr r1, =#0x3f003004    @ low counter in rpi2 TODO use rpi_iobase
+       ldr r0, [r1]
+       add r0, #4000           @ 1Mhz / 250hz = 4k counts
+       ldr r1, =#0x3f003010    @ compare 1 reg
+       str r0, [r1]
+
+       @ clear interrupt
+       ldr r1, =#0x3f003000
+       mov r0, #2      @ set bit 1 to clear interrupt from C1
+       str r0, [r1]
+
+       ldmfd sp!, {r0, r1}
+       subs pc, lr, #4
+
+intr_entry_fiq:
+       ldr r9, =num_ticks
+       ldr r8, [r9]
+       add r8, #1
+       str r8, [r9]
        subs pc, lr, #4
+
+@ vi:set ft=armasm: