Amber ARM-compatible core

Modified irq.S to test disabling irq. Program hangs on "bl disable_irq". lr does not have the right value. Please double check. ---Botao

#include "amber_registers.h"

.section .text
.globl  main

main:

    /* 0x00 Reset Interrupt vector address */
    b       start

    /* 0x04 Undefined Instruction Interrupt vector address */
    b       testfail

    /* 0x08 SWI Interrupt vector address */
    b       testfail

    /* 0x0c Prefetch abort Interrupt vector address */
    b       testfail

    /* 0x10 Data abort Interrupt vector address */
    b       testfail
    b       testfail

    /* 0x18 IRQ vector address */
    b       service_irq

    /* 0x1c FIRQ vector address */
    b       testfail

disable_irq: orr lr, lr, #0x08000000 mov pc, lr

start: / Set Supervisor Mode stack pointer / ldr sp, AdrSVCStack

    /* Switch to IRQ Mode */
    mov     r0, #0x00000002
    teqp    pc, r0
    /* Set IRQ Mode stack pointer */
    ldr     sp, AdrIRQStack

    /* Switch to User Mode */
    /* and unset interrupt mask bits */

    mov     r0,   #0x00000003
    teqp    pc, r0

    bl      disable_irq

(no changes below........) ldr r4, AdrRanNum ldr r5, r4 and r5, r5, #0x1c

I've recreated the bug and am working on a fix. Thanks for finding it.

The following code doesnot work due to the same bug(I believe)

(in supervisor mode here) mov r0, #0x08000002 teqp pc, r0 // move to irq mode sub lr, lr, #4 // lr doesnot change at all !!

Hopefully this is helpful.

Fix for Amber23 and Amber25 cores submitted. Users should update to the latest version to avoid this bug.