fighting with interrupt vectors

[rpikern] / src / startup.s

diff --git a/src/startup.s b/src/startup.s
index ec157f6..84e7e94 100644 (file)
--- a/src/startup.s
+++ b/src/startup.s
@@ -1,8 +1,54 @@
+       .extern main
+
        .section .startup
+       .code 32
+
+       .global startup
+startup:
+       cpsid if
+
+       @ stop all but one of the cores
+       mrc p15, 0, r0, c0, c0, 5
+       ands r0, r0, #0xff
+       bne exit
+
+       @ detect if we're running in hyp mode, and drop to svc
+       mrs r0, cpsr
+       and r1, r0, #0x1f
+       cmp r1, #0x1a
+       bne hypend
+
+       bic r0, #0x1f
+       orr r0, #0x13
+       @msr spsr_cxsf, r0
+       add r0, pc, #4
+       msr elr_hyp, r0
+       @eret
+       mov pc, r0
+hypend:
+
+       @ setup initial stacks, allow 4k stack for IRQs
+       @mov r0, #0x12  @ switch to IRQ mode
+       @msr cpsr, r0
+       @ldr sp, =_stacktop
+       @mov r0, #0x13  @ switch to supervisor mode
+       @msr cpsr, r0
+       ldr sp, =_stacktop - 4096
+
        @ clear bss
        ldr r0, =_bss_start
        ldr r1, =_bss_size
+       cmp r1, #0
+       beq 1f          @ 0-sized bss, skip clear
        mov r2, #0
 0:     str r2, [r0], #4
        subs r1, #4
        bne 0b
+1:
+       blx main
+
+       .global exit
+exit:  wfe
+       b exit
+
+@ vi:set filetype=armasm: