From c374eaacbc0d16983bbd1112fefa74dbe88e1e53 Mon Sep 17 00:00:00 2001
From: Wojtek Kosior <kwojtus@protonmail.com>
Date: Sat, 28 Dec 2019 15:55:29 +0100
Subject: use ldm instruction instead of libkernel for entering user mode; get
 rid of libkernel (no longer needed)

---
 psr.h | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

(limited to 'psr.h')

diff --git a/psr.h b/psr.h
index 9809fc4..b2adafb 100644
--- a/psr.h
+++ b/psr.h
@@ -64,4 +64,19 @@ inline static PSR_t read_CPSR(void)
   return CPSR;
 }
 
+inline static PSR_t read_SPSR(void)
+{
+  PSR_t SPSR;
+  // get content of saved program status register
+  asm("mrs %0, spsr" : "=r" (SPSR.raw) :: "memory");
+  
+  return SPSR;
+}
+
+inline static void write_SPSR(PSR_t SPSR)
+{
+  // set content of saved program status register
+  asm("msr spsr, %0" :: "r" (SPSR.raw));
+}
+
 #endif // PSR_H
-- 
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