Started multitasking

4 files changed, 98 insertions, 4 deletions

diff --git a/apps/Makefile b/apps/Makefile
index 574f135..56e5472 100644
--- a/apps/Makefile
+++ b/apps/Makefile
@@ -1,6 +1,6 @@
 # MIT License, Copyright (c) 2020 Marvin Borner
 
-COBJS = test.o
+COBJS = a.o b.o root.o
 CC = ../cross/opt/bin/i686-elf-gcc
 LD = ../cross/opt/bin/i686-elf-ld
 OC = ../cross/opt/bin/i686-elf-objcopy
@@ -10,7 +10,7 @@ CFLAGS = $(CSFLAGS) -Wall -Wextra -nostdlib -nostdinc -ffreestanding -ffunction-
 all: $(COBJS)
 
 %.o: %.c
-	@mkdir -p ../build/
+	@mkdir -p ../build/apps/
 	@$(CC) -c $(CFLAGS) $< -o $@
 	@$(LD) -o $(@:.o=.elf) -Tlink.ld $@
-	@$(OC) -O binary $(@:.o=.elf) ../build/$(@:.o=)
+	@$(OC) -O binary $(@:.o=.elf) ../build/apps/$(@:.o=)
diff --git a/apps/test.c b/apps/a.c
index ad84996..f09bb96 100644
--- a/apps/test.c
+++ b/apps/a.c
@@ -42,5 +42,5 @@ void serial_print(const char *data)
 
 void main()
 {
-	serial_print("Follow the white rabbit.");
+	serial_print("a");
 }
diff --git a/apps/b.c b/apps/b.c
new file mode 100644
index 0000000..3de20bf
--- /dev/null
+++ b/apps/b.c
@@ -0,0 +1,46 @@
+// MIT License, Copyright (c) 2020 Marvin Borner
+
+#include <def.h>
+
+u32 strlen(const char *s)
+{
+	const char *ss = s;
+	while (*ss)
+		ss++;
+	return ss - s;
+}
+
+u8 inb(u16 port)
+{
+	u8 value;
+	__asm__ volatile("inb %1, %0" : "=a"(value) : "Nd"(port));
+	return value;
+}
+
+void outb(u16 port, u8 data)
+{
+	__asm__ volatile("outb %0, %1" ::"a"(data), "Nd"(port));
+}
+
+int is_transmit_empty()
+{
+	return inb(0x3f8 + 5) & 0x20;
+}
+
+void serial_put(char ch)
+{
+	while (is_transmit_empty() == 0)
+		;
+	outb(0x3f8, (u8)ch);
+}
+
+void serial_print(const char *data)
+{
+	for (u32 i = 0; i < strlen(data); i++)
+		serial_put(data[i]);
+}
+
+void main()
+{
+	serial_print("b");
+}
diff --git a/apps/root.c b/apps/root.c
new file mode 100644
index 0000000..e7cbf4e
--- /dev/null
+++ b/apps/root.c
@@ -0,0 +1,48 @@
+// MIT License, Copyright (c) 2020 Marvin Borner
+
+#include <def.h>
+
+u32 strlen(const char *s)
+{
+	const char *ss = s;
+	while (*ss)
+		ss++;
+	return ss - s;
+}
+
+u8 inb(u16 port)
+{
+	u8 value;
+	__asm__ volatile("inb %1, %0" : "=a"(value) : "Nd"(port));
+	return value;
+}
+
+void outb(u16 port, u8 data)
+{
+	__asm__ volatile("outb %0, %1" ::"a"(data), "Nd"(port));
+}
+
+int is_transmit_empty()
+{
+	return inb(0x3f8 + 5) & 0x20;
+}
+
+void serial_put(char ch)
+{
+	while (is_transmit_empty() == 0)
+		;
+	outb(0x3f8, (u8)ch);
+}
+
+void serial_print(const char *data)
+{
+	for (u32 i = 0; i < strlen(data); i++)
+		serial_put(data[i]);
+}
+
+void main()
+{
+	serial_print("root loaded\n");
+	while (1) {
+	};
+}