kapstok / Bytecode-OS (public) (License: MIT) (since 2018-11-16) (hash sha1)
A bare-bone OS only capable of parsing bytecode.
Clone URLs: https://rocketgit.com/user/kapstok/Bytecode-OS ssh://rocketgit@ssh.rocketgit.com/user/kapstok/Bytecode-OS git://git.rocketgit.com/user/kapstok/Bytecode-OS
master
List of commits:
Subject Hash Author Date (UTC)
Initial commit. 41e0f7d15fac4a7cde4bd681c9df870103e0c072 Jan Allersma 2018-11-16 19:46:19
Commit 41e0f7d15fac4a7cde4bd681c9df870103e0c072 - Initial commit.
Author: Jan Allersma
Author date (UTC): 2018-11-16 19:46
Committer name: Jan Allersma
Committer date (UTC): 2018-11-16 19:46
Parent(s):
Signer:
Signing key:
Signing status: N
Tree: 3901b81a84f5636cb69bb17d49852d26c3a75279
File Lines added Lines deleted
.gitignore 12 0
MyVM.c 92 0
README.md 40 0
bootloader/Makefile 16 0
bootloader/main.asm 46 0
bootloader/readme.txt 9 0
prog.dat 0 0
shell/linux.txt 3 0
template.asm 5 0
vm.asm 18 0
File .gitignore added (mode: 100644) (index 0000000..4ef89f4)
1
2 Boot_programming/bootloader/build
3
4 Boot_programming/bootloader/*.iso
5
6 Boot_programming/bootloader/*.img
7
8 Boot_programming/bootloader/*.bin
9
10 *.o
11
12 dist
File MyVM.c added (mode: 100644) (index 0000000..eae6c1b)
1 // Compile cmd: gcc MyVM.c -o MyVM
2 // View vm: ./<filename> | xxd
3 // View bin files: xxd <filename>
4
5 #define NUM_REGS 4
6 #define BUF_SIZE 17
7 #include <stdio.h>
8 #include <stdlib.h>
9 //#include <fcntl.h> // For file read/write
10 //#include <unistd.h> // For file close
11
12 int regs[NUM_REGS];
13 ushort prog[] = {0x0000, 0x0000, 0x0000, 0x0000}; //{ 0x1064, 0x11c8, 0x2201, 0x0000 };
14
15 int pc = 0;
16 int fc = 0;
17 int running = 1;
18
19 int fetch() { return prog[pc++]; }
20
21 int instruction = 0;
22 int reg1 = 0;
23 int reg2 = 0;
24 int reg3 = 0;
25 int imm = 0;
26
27 void decode (int Instruction) {
28 instruction = (Instruction & 0xf000) >> 12;
29 reg1 = (Instruction & 0xf00) >> 8;
30 reg2 = (Instruction & 0xf0) >> 4;
31 reg3 = (Instruction & 0xf);
32 imm = (Instruction & 0xff);
33 }
34
35 void eval () {
36 switch(instruction) {
37 case 0: // instruction = halt
38 printf("halt\n");
39 running = 0;
40 break;
41 case 1: // instruction = loadi
42 printf("loadi r%d #%d\n", reg1, imm);
43 regs[reg1] = imm;
44 break;
45 case 2: // instruction = add
46 printf("add r%d r%d r%d\n", reg1, reg2, reg3);
47 regs[reg1] = regs[reg2] + regs[reg3];
48 break;
49 }
50 }
51
52 void showRegs () {
53 int i;
54 printf("regs = ");
55 for(i = 0; i < NUM_REGS; i++)
56 printf("%04x ", regs[i]);
57 printf("\n");
58 }
59
60 void run () {
61 while(running) {
62 showRegs();
63 int instruction = fetch();
64 decode(instruction);
65 eval();
66 }
67 }
68
69 void loadBin () {
70 char filename[] = { 'p', 'r', 'o', 'g', '.', 'd', 'a', 't' };
71 FILE* filedes;
72
73 printf("Loading binary..\n");
74
75 filedes = fopen(filename, "rb");
76
77 if(filedes == 0)
78 printf("loading failed :(");
79
80 for (int i = 0; i < sizeof(prog) / sizeof(prog[0]); i++) {
81 fread(&prog[i], sizeof(ushort), 1, filedes);
82 printf("%04x\n", prog[i]);
83 }
84 fclose(filedes);
85 printf("Done!\n");
86 }
87
88 int main (int argc, const char* argv[]) {
89 loadBin();
90 run();
91 return 0;
92 }
File README.md added (mode: 100644) (index 0000000..973a88e)
1 # Bytecode OS
2
3 This Readme is separated in two parts:
4
5 * The Bytecode part, which shows how to write a binary file and parse it with
6 an executable.
7
8 * The OS part, which shows how to create a bare-bone OS that uses the Bytecode
9 part.
10
11 If you consider the bare-bone OS as an actual OS, then you could say that the
12 executable from the bytecode part is basically a virtual machine.
13
14 ## The bytecode part
15
16 ### Building
17
18 <placeholder>
19
20 ### Bytecode reference
21
22 `prog.dat` is an example (binary) file that can be read by the executable.
23 The reference of the bytecode can be found below:
24
25 ```
26 #!Virtual Machine
27
28 VM bytecode prog bytecode description
29
30 1064 6410 1 - loadi, 0 - arg0 (register), 64 - value
31 11c8 c811 1 - loadi, 1 - arg0 (register), c8 - value
32 2201 0122 2 - add, 2 - arg0 (result register), 0 - arg1 (register 1), 1 - arg2 (register 2)
33 0000 0000 0000 - halt
34 ```
35
36 ## The OS part
37
38 ### Building
39
40 <placeholder>
File bootloader/Makefile added (mode: 100644) (index 0000000..0334773)
1 SOURCE = main.asm
2 BIN = allersmaboot.bin
3 IMG = myos
4 VOLUMELABEL = MYOS
5 BUILDDIR = build
6
7 all:
8 mkdir ${BUILDDIR}
9 nasm -f bin -o ${BIN} ${SOURCE}
10 dd bs=1024 if=/dev/zero of=${IMG}.img count=1440
11 dd if=${BIN} of=${IMG}.img seek=0 count=1 conv=notrunc
12 cp ${IMG}.img ${BUILDDIR}
13 genisoimage -quiet -V \'${VOLUMELABEL}\' -input-charset iso8859-1 -o ${IMG}.iso -b ${IMG}.img -hide ${IMG}.img ${BUILDDIR}
14
15 clean:
16 rm -R ${BUILDDIR}
File bootloader/main.asm added (mode: 100644) (index 0000000..2edf55f)
1 ; Te compileren met NASM: nasm -f bin -o allersmaboot.bin main.asm
2 BITS 16
3
4 start:
5 ; Define Stack Space
6 mov ax, 07C0h ; De initial location van deze bootloader (ax = 0x7C00 / BITS).
7 add ax, 20h ; Einde bootloader data (ds).
8 mov ss, ax ; ss = Stack Space Location. Hier begint de stack.
9 mov sp, 4096 ; Stack Pointer. Werkt achterstevoren; begint dus bij einde.
10
11 ; Define Data Space
12 mov ax, 07C0h
13 mov ds, ax ; ds = Data Space Location. Hier begint de data.
14
15 ; Print string
16 mov si, message ; si = Source Index register.
17 call print
18 call read
19 cli ; Disable External interrupts
20 hlt ; Halt CPU.
21
22 data:
23 message db 'Bootloader booted.',0
24
25 read:
26 mov ah, 0h ; Get char
27 int 16h ; puts(char)
28 mov ah, 0Eh;call print ; display(char)
29 int 10h ; echo char
30 jmp read ; start over again.
31
32 print:
33 mov ah, 0Eh
34
35 .printchar:
36 lodsb ; Load byte from Source Index & increment it.
37 cmp al, 0 ; Compare al with NULL.
38 je .done ; if(cmp al, 0) { .done; }
39 int 10h ; puts(loaded_byte);
40 jmp .printchar
41
42 .done:
43 ret
44
45 times 510-($-$$) db 0 ; Fill 510 bytes with this bootloader.
46 dw 0xAA55 ; Bootloader signature: EOF & Geeft aan dat dit een bootloader is.
File bootloader/readme.txt added (mode: 100644) (index 0000000..d101288)
1 cd bootloader
2 nasm -f bin -o allersmaboot.bin main.asm
3 dd bs=1024 if=/dev/zero of=myos.img count=1440 # Creating 1024B*1440B=1440KB image..
4 dd if=allersmaboot.bin of=myos.img seek=0 count=1 conv=notrunc
5 mkdir iso
6 cp myos.img iso
7 genisoimage -quiet -V 'MYOS' -input-charset iso8859-1 \
8 -o myos.iso -b myos.img -hide myos.img iso
9 rm iso # evt
File prog.dat added (mode: 100644) (index 0000000..ed6c9f1)
File shell/linux.txt added (mode: 100644) (index 0000000..7c2c8e2)
1 nasm -f elf vm.asm -o dist/linux.o
2 gcc -o dist/linux.elf dist/linux.o -nostartfiles -nostdlib -nodefaultlibs -m32 -Os
3 strip -s dist/linux.elf
File template.asm added (mode: 100644) (index 0000000..d014305)
1 SECTION .data ; initial vars
2
3 SECTION .bss ; not initialized vars
4
5 SECTION .text ; code\
File vm.asm added (mode: 100644) (index 0000000..1d1e068)
1 SECTION .data ; initial vars
2
3 msg: db "Dit is een test",10
4 len: equ $-msg
5
6 SECTION .text ; code
7
8 global main
9 main:
10 mov edx, len
11 mov ecx, msg
12 mov ebx, 1
13 mov eax, 4
14
15 int 0x80
16 mov ebx, 0
17 mov eax, 1
18 int 0x80
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