From b8f00b77e965c73a047e71193c8c6e2d7488f34d Mon Sep 17 00:00:00 2001
From: Marvin Borner
Date: Fri, 4 Sep 2020 15:50:21 +0200
Subject: Added mandelbrot demo and fpu driver

---
 kernel/Makefile      |  1 +
 kernel/drivers/fpu.c | 24 ++++++++++++++++++++++++
 kernel/inc/fpu.h     |  8 ++++++++
 kernel/main.c        |  2 ++
 4 files changed, 35 insertions(+)
 create mode 100644 kernel/drivers/fpu.c
 create mode 100644 kernel/inc/fpu.h

(limited to 'kernel')

diff --git a/kernel/Makefile b/kernel/Makefile
index 07f985a..98060df 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -3,6 +3,7 @@
 COBJS = main.o \
 	drivers/interrupts.o \
 	drivers/interrupts_asm.o \
+	drivers/fpu.o \
 	drivers/keyboard.o \
 	drivers/mouse.o \
 	drivers/ide.o \
diff --git a/kernel/drivers/fpu.c b/kernel/drivers/fpu.c
new file mode 100644
index 0000000..d8a2b79
--- /dev/null
+++ b/kernel/drivers/fpu.c
@@ -0,0 +1,24 @@
+// MIT License, Copyright (c) 2020 Marvin Borner
+
+#include <def.h>
+
+void set_fpu_cw(const u16 cw)
+{
+	__asm__ volatile("fldcw %0" ::"m"(cw));
+}
+
+void fpu_install()
+{
+	__asm__ volatile("clts");
+	u32 t;
+	__asm__ volatile("mov %%cr0, %0" : "=r"(t));
+	t &= ~(1 << 2);
+	t |= (1 << 1);
+	__asm__ volatile("mov %0, %%cr0" ::"r"(t));
+
+	__asm__ volatile("mov %%cr4, %0" : "=r"(t));
+	t |= 3 << 9;
+	__asm__ volatile("mov %0, %%cr4" ::"r"(t));
+
+	__asm__ volatile("fninit");
+}
diff --git a/kernel/inc/fpu.h b/kernel/inc/fpu.h
new file mode 100644
index 0000000..d747708
--- /dev/null
+++ b/kernel/inc/fpu.h
@@ -0,0 +1,8 @@
+// MIT License, Copyright (c) 2020 Marvin Borner
+
+#ifndef FPU_H
+#define FPU_H
+
+void fpu_install();
+
+#endif
diff --git a/kernel/main.c b/kernel/main.c
index 7d87be5..4792d75 100644
--- a/kernel/main.c
+++ b/kernel/main.c
@@ -2,6 +2,7 @@
 
 #include <boot.h>
 #include <cpu.h>
+#include <fpu.h>
 #include <fs.h>
 #include <keyboard.h>
 #include <load.h>
@@ -23,6 +24,7 @@ void kernel_main(struct vid_info *vid_info)
 
 	// Install drivers
 	interrupts_install();
+	fpu_install();
 	timer_install();
 	keyboard_install();
 	mouse_install();
-- 
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