From aca525d3ce745d4c622b15394a92b3c946e11854 Mon Sep 17 00:00:00 2001
From: xamidev <121681048+xamidev@users.noreply.github.com>
Date: Mon, 20 May 2024 21:48:48 +0200
Subject: [PATCH] Add: nonworking serial port driver implementation

---
 bochslog.txt        |  89 ++++++++++++++++++++++----------------------
 bochsrc.txt         |   1 +
 io.h                |   1 +
 io.s                |   7 ++++
 iso/boot/kernel.elf | Bin 9780 -> 10060 bytes
 kernel.elf          | Bin 9780 -> 10060 bytes
 kmain.c             |   2 +
 makefile            |   2 +-
 os.iso              | Bin 485376 -> 485376 bytes
 serial.c            |  68 +++++++++++++++++++++++++++++++++
 serial.h            |  20 ++++++++++
 11 files changed, 145 insertions(+), 45 deletions(-)
 create mode 100644 serial.c
 create mode 100644 serial.h

diff --git a/bochslog.txt b/bochslog.txt
index 14f0b6a..4b8de77 100644
--- a/bochslog.txt
+++ b/bochslog.txt
@@ -44,45 +44,45 @@
 00000000000i[USBCTL] Pluggable USB devices
 00000000000i[USBCTL]   mouse tablet keypad keyboard floppy disk cdrom printer
 00000000000i[USBCTL]   hub
-00000000000i[MEM0  ] allocated memory at 0x7f59fd3dc010. after alignment, vector=0x7f59fd3dd000
+00000000000i[MEM0  ] allocated memory at 0x7fb8f1ddd010. after alignment, vector=0x7fb8f1dde000
 00000000000i[MEM0  ] 32.00MB
 00000000000i[MEM0  ] mem block size = 0x00020000, blocks=256
 00000000000i[MEM0  ] rom at 0xffff0000/65536 ('/usr/share/bochs/BIOS-bochs-legacy')
 00000000000i[CPU0  ] WARNING: 3DNow! is not implemented yet !
 00000000000i[DEV   ] will paste characters every 100 iodev timer ticks
-00000000000i[      ] lt_dlhandle is 0x555b0a2aef10
+00000000000i[      ] lt_dlhandle is 0x5638a94a38b0
 00000000000i[PLUGIN] loaded plugin libbx_soundalsa.so
 00000000000i[WAVOUT] ALSA: opened default PCM output device
 00000000000i[WAVOUT] changed sample rate to 44101
-00000000000i[      ] lt_dlhandle is 0x555b0aa651a0
+00000000000i[      ] lt_dlhandle is 0x5638a9c59430
 00000000000i[PLUGIN] loaded plugin libbx_pci.so
-00000000000i[      ] lt_dlhandle is 0x555b0a2aeff0
+00000000000i[      ] lt_dlhandle is 0x5638a94a3990
 00000000000i[PLUGIN] loaded plugin libbx_pci2isa.so
-00000000000i[      ] lt_dlhandle is 0x555b0a22cea0
+00000000000i[      ] lt_dlhandle is 0x5638a9421ac0
 00000000000i[PLUGIN] loaded plugin libbx_usb_uhci.so
-00000000000i[      ] lt_dlhandle is 0x555b0a2c91b0
+00000000000i[      ] lt_dlhandle is 0x5638a94bdfc0
 00000000000i[PLUGIN] loaded plugin libbx_acpi.so
-00000000000i[      ] lt_dlhandle is 0x555b0a22c2a0
+00000000000i[      ] lt_dlhandle is 0x5638a9420ec0
 00000000000i[PLUGIN] loaded plugin libbx_hpet.so
-00000000000i[      ] lt_dlhandle is 0x555b0aa6f950
+00000000000i[      ] lt_dlhandle is 0x5638a9c63be0
 00000000000i[PLUGIN] loaded plugin libbx_cmos.so
-00000000000i[      ] lt_dlhandle is 0x555b0aa70160
+00000000000i[      ] lt_dlhandle is 0x5638a9c643f0
 00000000000i[PLUGIN] loaded plugin libbx_dma.so
-00000000000i[      ] lt_dlhandle is 0x555b0aa70970
+00000000000i[      ] lt_dlhandle is 0x5638a9c64d60
 00000000000i[PLUGIN] loaded plugin libbx_pic.so
-00000000000i[      ] lt_dlhandle is 0x555b0aa71130
+00000000000i[      ] lt_dlhandle is 0x5638a9c65520
 00000000000i[PLUGIN] loaded plugin libbx_pit.so
-00000000000i[      ] lt_dlhandle is 0x555b0aa71b50
+00000000000i[      ] lt_dlhandle is 0x5638a9c65f40
 00000000000i[PLUGIN] loaded plugin libbx_vga.so
-00000000000i[      ] lt_dlhandle is 0x555b0aa93190
+00000000000i[      ] lt_dlhandle is 0x5638a9c87580
 00000000000i[PLUGIN] loaded plugin libbx_floppy.so
-00000000000i[      ] lt_dlhandle is 0x555b0aa939d0
+00000000000i[      ] lt_dlhandle is 0x5638a9c87dc0
 00000000000i[PLUGIN] loaded plugin libbx_ioapic.so
-00000000000i[      ] lt_dlhandle is 0x555b0aa941e0
+00000000000i[      ] lt_dlhandle is 0x5638a9c885d0
 00000000000i[PLUGIN] loaded plugin libbx_keyboard.so
-00000000000i[      ] lt_dlhandle is 0x555b0aa94ae0
+00000000000i[      ] lt_dlhandle is 0x5638a9c88ed0
 00000000000i[PLUGIN] loaded plugin libbx_harddrv.so
-00000000000i[      ] lt_dlhandle is 0x555b0aa96bb0
+00000000000i[      ] lt_dlhandle is 0x5638a9c8afa0
 00000000000i[PLUGIN] loaded plugin libbx_pci_ide.so
 00000000000i[PLUGIN] init_dev of 'pci' plugin device by virtual method
 00000000000i[DEV   ] i440FX PMC present at device 0, function 0
@@ -90,7 +90,7 @@
 00000000000i[DEV   ] PIIX3 PCI-to-ISA bridge present at device 1, function 0
 00000000000i[PLUGIN] init_dev of 'cmos' plugin device by virtual method
 00000000000i[CMOS  ] Using local time for initial clock
-00000000000i[CMOS  ] Setting initial clock to: Sun May 19 15:09:18 2024 (time0=1716124158)
+00000000000i[CMOS  ] Setting initial clock to: Mon May 20 21:48:15 2024 (time0=1716234495)
 00000000000i[PLUGIN] init_dev of 'dma' plugin device by virtual method
 00000000000i[DMA   ] channel 4 used by cascade
 00000000000i[PLUGIN] init_dev of 'pic' plugin device by virtual method
@@ -133,7 +133,7 @@
 00000000000i[PAR   ] parallel port 1 at 0x0378 irq 7
 00000000000i[PLUGIN] init_dev of 'biosdev' plugin device by virtual method
 00000000000i[PLUGIN] init_dev of 'serial' plugin device by virtual method
-00000000000i[SER   ] com1 at 0x03f8 irq 4 (mode: null)
+00000000000i[SER   ] com1 at 0x03f8 irq 4 (mode: file)
 00000000000i[PLUGIN] init_dev of 'extfpuirq' plugin device by virtual method
 00000000000i[PLUGIN] init_dev of 'gameport' plugin device by virtual method
 00000000000i[PLUGIN] init_dev of 'usb_uhci' plugin device by virtual method
@@ -247,28 +247,29 @@
 00000443015i[BXVGA ] VBE known Display Interface b0c0
 00000443047i[BXVGA ] VBE known Display Interface b0c5
 00000445690i[VBIOS ] VBE Bios $Id: vbe.c 292 2021-06-03 12:24:22Z vruppert $
-00004097883i[BIOS  ] IDE time out
-00716758940i[BIOS  ] Booting from 07c0:0000
-00716854324i[BIOS  ] int13_harddisk: function 41, unmapped device for ELDL=80
-00716857995i[BIOS  ] int13_harddisk: function 08, unmapped device for ELDL=80
-00716861666i[BIOS  ] *** int 15h function AX=00c0, BX=0000 not yet supported!
-00842722000p[SDL2  ] >>PANIC<< User requested shutdown.
-00842722000i[CPU0  ] CPU is in protected mode (active)
-00842722000i[CPU0  ] CS.mode = 32 bit
-00842722000i[CPU0  ] SS.mode = 32 bit
-00842722000i[CPU0  ] EFER   = 0x00000000
-00842722000i[CPU0  ] | EAX=0000002a  EBX=0002cd80  ECX=000000f0  EDX=000003d5
-00842722000i[CPU0  ] | ESP=00067ecc  EBP=00067ee0  ESI=0002ced8  EDI=0002ced9
-00842722000i[CPU0  ] | IOPL=0 id vip vif ac vm rf nt of df if tf sf zf af pf cf
-00842722000i[CPU0  ] | SEG sltr(index|ti|rpl)     base    limit G D
-00842722000i[CPU0  ] |  CS:0008( 0001| 0|  0) 00000000 ffffffff 1 1
-00842722000i[CPU0  ] |  DS:0010( 0002| 0|  0) 00000000 ffffffff 1 1
-00842722000i[CPU0  ] |  SS:0010( 0002| 0|  0) 00000000 ffffffff 1 1
-00842722000i[CPU0  ] |  ES:0010( 0002| 0|  0) 00000000 ffffffff 1 1
-00842722000i[CPU0  ] |  FS:0010( 0002| 0|  0) 00000000 ffffffff 1 1
-00842722000i[CPU0  ] |  GS:0010( 0002| 0|  0) 00000000 ffffffff 1 1
-00842722000i[CPU0  ] | EIP=001004ab (001004ab)
-00842722000i[CPU0  ] | CR0=0x60000011 CR2=0x00000000
-00842722000i[CPU0  ] | CR3=0x00000000 CR4=0x00000000
-00842722000i[CMOS  ] Last time is 1716125000 (Sun May 19 15:23:20 2024)
-00842722000i[SIM   ] quit_sim called with exit code 1
+00004097906i[BIOS  ] IDE time out
+00685117203i[BIOS  ] Booting from 07c0:0000
+00685212587i[BIOS  ] int13_harddisk: function 41, unmapped device for ELDL=80
+00685216258i[BIOS  ] int13_harddisk: function 08, unmapped device for ELDL=80
+00685219929i[BIOS  ] *** int 15h function AX=00c0, BX=0000 not yet supported!
+00867137284i[      ] Ctrl-C detected in signal handler.
+00867137285i[      ] dbg: Quit
+00867137285i[CPU0  ] CPU is in protected mode (active)
+00867137285i[CPU0  ] CS.mode = 32 bit
+00867137285i[CPU0  ] SS.mode = 32 bit
+00867137285i[CPU0  ] EFER   = 0x00000000
+00867137285i[CPU0  ] | EAX=0000002a  EBX=0002cd80  ECX=000000f0  EDX=00000006
+00867137285i[CPU0  ] | ESP=00067ecc  EBP=00067ee0  ESI=0002ced8  EDI=0002ced9
+00867137285i[CPU0  ] | IOPL=0 id vip vif ac vm rf nt of df if tf sf zf af pf cf
+00867137285i[CPU0  ] | SEG sltr(index|ti|rpl)     base    limit G D
+00867137285i[CPU0  ] |  CS:0008( 0001| 0|  0) 00000000 ffffffff 1 1
+00867137285i[CPU0  ] |  DS:0010( 0002| 0|  0) 00000000 ffffffff 1 1
+00867137285i[CPU0  ] |  SS:0010( 0002| 0|  0) 00000000 ffffffff 1 1
+00867137285i[CPU0  ] |  ES:0010( 0002| 0|  0) 00000000 ffffffff 1 1
+00867137285i[CPU0  ] |  FS:0010( 0002| 0|  0) 00000000 ffffffff 1 1
+00867137285i[CPU0  ] |  GS:0010( 0002| 0|  0) 00000000 ffffffff 1 1
+00867137285i[CPU0  ] | EIP=001006cb (001006cb)
+00867137285i[CPU0  ] | CR0=0x60000011 CR2=0x00000000
+00867137285i[CPU0  ] | CR3=0x00000000 CR4=0x00000000
+00867137285i[CMOS  ] Last time is 1716235362 (Mon May 20 22:02:42 2024)
+00867137285i[SIM   ] quit_sim called with exit code 0
diff --git a/bochsrc.txt b/bochsrc.txt
index 362f256..fe783a2 100644
--- a/bochsrc.txt
+++ b/bochsrc.txt
@@ -7,3 +7,4 @@ boot:            cdrom
 log:             bochslog.txt
 clock:           sync=realtime, time0=local
 cpu:             count=1, ips=1000000
+com1:            enabled=1, mode=file, dev=com1.out
diff --git a/io.h b/io.h
index 1ad2ff3..17894e6 100644
--- a/io.h
+++ b/io.h
@@ -2,5 +2,6 @@
 #define INCLUDE_IO_H
 
 void outb(unsigned short port, unsigned char data);
+unsigned char inb(unsigned short port);
 
 #endif
diff --git a/io.s b/io.s
index 8ee142f..1cac568 100644
--- a/io.s
+++ b/io.s
@@ -5,3 +5,10 @@ outb:
   mov dx, [esp + 4]
   out dx, al
   ret
+
+global inb
+
+inb:
+  mov dx, [esp + 4]
+  in al, dx
+  ret
diff --git a/iso/boot/kernel.elf b/iso/boot/kernel.elf
index 85511f93eeccdeff49642c58508bbb6722ae0989..db82abfcc5cf29e81be5a5ea4751021849c802b7 100755
GIT binary patch
delta 2114
zcmah~e{54#6u$5E$GTG1$F|NPlg+k^aY5Kn1fwxv)?`tJ&18|7klH~@i(QA^#)iqL
z^MNu31h@%76T=@uKq7I(W#bPeNQYB_Wa3X^oJxjyN;QKtgpR@UJMXPqH!wEY?)|>=
zednBa?tN|V$_uOZ7F!3*5_^I%R$ac&=`^p&Wo%9E$>&eoR~|Mq)|t3vXG|#-7?YE>
z-SS&ERn@CpHUJJta?-L<*exH_xFaTw>-Jc>*N%UcsPDS^lAJ75d|HxE_;Shp>VR&u
z_j_&zKUXaFzB9<+4Sf$<IX0Ej9{P@$15@g0%B?!TH&aGV8kJ!bH!b7?Qf1CD+TP0J
zx1~inQS3VtXL;3}{kfNo;2+Inj9--I&Ka`zv9;8sa)S6fv!O5Lj(oeho$!~uBL7;B
zj7pt}A9+c^4>`w0&||ZBy5RBBoz-qjuzR)J_)kJxl9WhJO3KS5I?8Jb%j22nF9X$?
zXqm-WcfF<CV+(fGr-EIcQ4Ap^pE20`X$GM;F@LYJO;uHl6`@gmK0}%+X{qxnp{ba?
zFN^o;{NyyWp?@sI(THl*ic&>;e|<_mi)xqX%nWs138nac#x|U@Y4AUMp+R&>)?e;w
zeNM0W3|V(&tnvHSJaRvyk&LS|#*ELT^=hMXZ|E+%1izJKP94wbR?eZJ&cs~u(qug&
znAZqBp&0in9TPT<vU!y&Gq81XqOc&oM8|`k6tc2wOSSV#33OBRiBo2r#P4@9r!>vC
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z4biUuNfd(S189!UC?+1#s-4_-+{}ftLu)BaA0xZ2R$&!;PR!E?;Ai#C#Q*DRHFkGj
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z>`-L2z`w#kXG4ZpfR|@Yzz6&-3eeT2_y*vQvKndx_F#f<PsFzXKa2?tPvEV<+mMeg
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z$L-9eo6=i^1LrHs3it)L&3p>XsUkk?c3Ow99YS!2$gSmH<o4hl!Ved-^ULM)Oi3qW
Q-|%#~%k-I>v3JP-FY?fiTL1t6

delta 1078
zcmYk5Ur1AN6vxlK`|F&$cXLhCmFw<KQ3R(IBvzoz9!gD8>q$~;GGi$Ckn|)r?cXw%
z#|MclM0@HF3ZXAyky!~P5oJD9AS4VNp%fC#bvr-rG%wpd=W~AF@A>_?_r9xnS{2DO
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z#@tN9_2s%y%pR@VG`zujQRd#_B{AFgNEL=+#tTB=6G8NjS`nry*M-R!G*BD(%<7lb
zdSt6%D5i~mq?)b*7e%k(E=$b<3f3Y+3*|jC3s`9#NO{jw{fGqsm&D!T2VoK#*>a*I
ztZqe%)rI*sK_6uJ6_46h3|+L9o|zT&rY{)o(YAFKGp5=1J6j{IksChQ*cz^vwLe*t
zP)v;0FvT>UwR;=^e=yi#YUymg=r^_dyG&gjox$^fqYjyGh~u0iZ<jZ&D8*!ea*MH#
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zNbM+K=%lq*lYDijoR4klT~s?v<9iZl%ar&p37X1*RhdrySAsQ|z>yT>T=%Q_@yFTB
z53r^jRFmX=O(~=7@5xg?)WVwLV~MB|)1RjFA-yl^rG*wuxN^EX2(_YG<-h=a#8YG|
zrDy{V`YEnx{__B_*((BV60Bf^A&P^^t~Oo+Pnez)p@bsyPf@%^<Eoy6m&8ExsjTmY
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z{%1I_P@$L>a3v|oB2J?nvx%4?hnRh5>|*QAB{uFjfkI+7!rmUHFCi|&C8+@I?sgn@
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wLzE8Laor=C#wi^q-8hF*?&}mUeJQDAx8PcCwk{|El%h4yt$W}GxXN1n1Ai3kumAu6

diff --git a/kernel.elf b/kernel.elf
index 85511f93eeccdeff49642c58508bbb6722ae0989..db82abfcc5cf29e81be5a5ea4751021849c802b7 100755
GIT binary patch
delta 2114
zcmah~e{54#6u$5E$GTG1$F|NPlg+k^aY5Kn1fwxv)?`tJ&18|7klH~@i(QA^#)iqL
z^MNu31h@%76T=@uKq7I(W#bPeNQYB_Wa3X^oJxjyN;QKtgpR@UJMXPqH!wEY?)|>=
zednBa?tN|V$_uOZ7F!3*5_^I%R$ac&=`^p&Wo%9E$>&eoR~|Mq)|t3vXG|#-7?YE>
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zx1~inQS3VtXL;3}{kfNo;2+Inj9--I&Ka`zv9;8sa)S6fv!O5Lj(oeho$!~uBL7;B
zj7pt}A9+c^4>`w0&||ZBy5RBBoz-qjuzR)J_)kJxl9WhJO3KS5I?8Jb%j22nF9X$?
zXqm-WcfF<CV+(fGr-EIcQ4Ap^pE20`X$GM;F@LYJO;uHl6`@gmK0}%+X{qxnp{ba?
zFN^o;{NyyWp?@sI(THl*ic&>;e|<_mi)xqX%nWs138nac#x|U@Y4AUMp+R&>)?e;w
zeNM0W3|V(&tnvHSJaRvyk&LS|#*ELT^=hMXZ|E+%1izJKP94wbR?eZJ&cs~u(qug&
znAZqBp&0in9TPT<vU!y&Gq81XqOc&oM8|`k6tc2wOSSV#33OBRiBo2r#P4@9r!>vC
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zi_rLORc+0-qCc_mT!PAx{U>N@$5nON49zB8qG`sV@k8_U3{7*EhF+KU>3LRb!^lol
z4biUuNfd(S189!UC?+1#s-4_-+{}ftLu)BaA0xZ2R$&!;PR!E?;Ai#C#Q*DRHFkGj
ztQ*P1YiT3th(Yhe_B_5#^^cLg#{VuWjkg0DC7l&m4%<U2*q*|g&jfY=>kCFbE&;y>
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Q-|%#~%k-I>v3JP-FY?fiTL1t6

delta 1078
zcmYk5Ur1AN6vxlK`|F&$cXLhCmFw<KQ3R(IBvzoz9!gD8>q$~;GGi$Ckn|)r?cXw%
z#|MclM0@HF3ZXAyky!~P5oJD9AS4VNp%fC#bvr-rG%wpd=W~AF@A>_?_r9xnS{2DO
zjcG+V004#ZZAsEM=>eMb6UV28L%mvno|!)aKs1#D2*u3(p|;<OQX8Gs5WW(_mBw)6
z#@tN9_2s%y%pR@VG`zujQRd#_B{AFgNEL=+#tTB=6G8NjS`nry*M-R!G*BD(%<7lb
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diff --git a/kmain.c b/kmain.c
index ad503d5..b808037 100644
--- a/kmain.c
+++ b/kmain.c
@@ -1,8 +1,10 @@
 #include "stdio.h"
+#include "serial.h"
 
 int kmain(int retvalue)
 {
   clear();
   puts("hello\nbrave\nnew\nworld");
+  serial_write("hello", 1);
   return retvalue;
 }
diff --git a/makefile b/makefile
index 446ffe8..1559535 100644
--- a/makefile
+++ b/makefile
@@ -1,4 +1,4 @@
-OBJECTS = loader.o kmain.o stdio.o io.o string.o 
+OBJECTS = loader.o kmain.o stdio.o io.o string.o serial.o 
 CC = gcc
 CFLAGS = -m32 -nostdlib -nostdinc -fno-builtin -fno-stack-protector -nostartfiles -nodefaultlibs -Wall -Wextra -c
 LDFLAGS = -T link.ld -melf_i386
diff --git a/os.iso b/os.iso
index 373e266038b25355364a0d8979babe51d242d37e..eee9753aeedec904939dbf20a4615d612a7e68e4 100644
GIT binary patch
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diff --git a/serial.c b/serial.c
new file mode 100644
index 0000000..2df309b
--- /dev/null
+++ b/serial.c
@@ -0,0 +1,68 @@
+#include "io.h"
+#include "serial.h"
+
+void serial_configure_baud_rate(unsigned short com, unsigned short divisor)
+{
+  outb(SERIAL_LINE_CMD_PORT(com), SERIAL_LINE_ENABLE_DLAB);
+  outb(SERIAL_DATA_PORT(com), (divisor >> 8) & 0x00FF);
+  outb(SERIAL_DATA_PORT(com), divisor & 0x00FF);
+}
+
+void serial_configure_line(unsigned short com)
+{
+  /*
+  d b p   s dl
+  0 0 000 0 11 = 0x03
+  
+  Length 8 bits, no parity bit, one stop bit, break control off
+  */
+
+  outb(SERIAL_LINE_CMD_PORT(com), 0x03);
+}
+
+void serial_configure_buffer(unsigned short com)
+{
+  /*
+  lv b r d c c e
+  11 0 0 0 1 1 1 = 0xC7
+  
+  Enable FIFO, clear FIFO queues, use 14 bytes as queue size
+  */
+
+  outb(SERIAL_LINE_CMD_PORT(com), 0xC7);
+}
+
+void serial_configure_modem(unsigned short com)
+{
+  /*
+  
+  r r a l a a r d
+  0 0 0 0 0 0 1 1 = 0x03
+
+  Ready to transmit, data terminal ready
+  */
+
+  outb(SERIAL_LINE_CMD_PORT(com), 0x03);
+}
+
+int serial_is_transmit_fifo_empty(unsigned short com)
+{
+  return (inb(SERIAL_LINE_STATUS_PORT(com)) & 0x20);
+}
+
+void serial_write(const char* buf, unsigned short com)
+{
+  serial_configure_baud_rate(com, 2);
+  serial_configure_line(com);
+  serial_configure_buffer(com);
+  serial_configure_modem(com);
+
+  for (unsigned int i = 0; i<sizeof(buf); i++)
+  {
+    while (serial_is_transmit_fifo_empty(com))
+    {
+      outb(SERIAL_DATA_PORT(com), buf[i]);
+    }
+  }
+  return;
+}
diff --git a/serial.h b/serial.h
new file mode 100644
index 0000000..5832fb6
--- /dev/null
+++ b/serial.h
@@ -0,0 +1,20 @@
+#ifndef INCLUDE_SERIAL_H
+#define INCLUDE_SERIAL_H
+
+#define SERIAL_COM1_BASE              0x3F8
+#define SERIAL_DATA_PORT(base)        (base)
+#define SERIAL_FIFO_CMD_PORT(base)    (base + 2)
+#define SERIAL_LINE_CMD_PORT(base)    (base + 3)
+#define SERIAL_MODEM_CMD_PORT(base)   (base + 4)
+#define SERIAL_LINE_STATUS_PORT(base) (base + 5)
+
+#define SERIAL_LINE_ENABLE_DLAB       0x80
+
+void serial_configure_baud_rate(unsigned short com, unsigned short divisor);
+void serial_configure_line(unsigned short com);
+void serial_configure_buffer(unsigned short com);
+void serial_configure_modem(unsigned short com);
+int serial_is_transmit_fifo_empty(unsigned short com);
+void serial_write(const char* buf, unsigned short com);
+
+#endif