From 096971203495ea7b5b9f2e6ec4efe1241f1919a6 Mon Sep 17 00:00:00 2001 From: Wojtek Kosior Date: Tue, 22 Oct 2019 17:50:28 +0200 Subject: add processor mode changing --- cpsr.h | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) create mode 100644 cpsr.h (limited to 'cpsr.h') diff --git a/cpsr.h b/cpsr.h new file mode 100644 index 0000000..327bdf0 --- /dev/null +++ b/cpsr.h @@ -0,0 +1,39 @@ +#include + +enum execution_mode { + MODE_USER = 0x10, + MODE_FIQ = 0x11, + MODE_IRQ = 0x12, + MODE_SUPERVISOR = 0x13, + MODE_MONITOR = 0x16, + MODE_ABORT = 0x17, + MODE_HYPERVISOR = 0x1a, + MODE_UNDEFINED = 0x1b, + MODE_SYSTEM = 0x1f, +}; + +inline static uint32_t read_CPSR(void) +{ + uint32_t CPSR; + // get content of current program status register + asm("mrs %0, cpsr" : "=r" (CPSR) ::); + + return CPSR; +} + +inline static enum execution_mode read_processor_mode(void) +{ + /* lowest 5 bits indicate processor mode */ + return read_CPSR() & 0x1f; +} + +inline static void set_system_mode(void) +{ + uint32_t CPSR = read_CPSR(); + + CPSR = (CPSR >> 5) << 5; + + CPSR |= MODE_SYSTEM; + + asm("msr cpsr, %0" :: "r" (CPSR) : "memory"); +} -- cgit v1.2.3