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boot.src
1 f 100,700 0 2 a 3 ;;;; first we bring in our C program (300-700) ;;;; 4 5 n a.bin 6 l 300 7 8 a 9 ;;;; then the floppy parameter table (103-13F) ;;;; 10 ; parameters taken from a FREEDOS formatted 1.44M ; 11 12 e 103 46 52 44 4F 53 13 e 108 34 2E 31 00 02 01 01 00 14 e 110 02 E0 00 40 0B f0 09 00 15 e 118 12 00 02 00 00 00 00 00 16 e 120 00 00 00 00 00 00 29 12 17 e 128 15 5D 33 45 4D 50 54 59 18 e 130 44 49 53 4B 20 20 46 41 19 e 138 54 31 32 20 20 20 31 C0 20 21 a 22 ;;;; now we assemble the boot sector ;;;; 23 24 a 100 25 jmp 140 ; skip over the floppy parameters 26 27 a 140 28 ; == floppy I/O == 29 xor dx,dx 30 mov es,dx 31 mov cx,02 32 mov bx,7e00 33 mov ax,0202 34 int 13 ; read the next (al=2) sectors... 35 mov dx,03f2 36 xor ax,ax 37 out dx,al ; ... then turn off the floppy 38 jmp 0:7c80 39 40 41 a 180 42 ; == enter protected mode == 43 cli ; turn off interrupts 44 ; load GDT (using CS override) 45 db 2e, 0f, 01, 16, 00, 7d 46 ; set pmode bit in cr0 47 db 0f, 20, c0 48 or al, 1 49 db 0f, 22, c0 50 ; load 32-bit data segment registers, and... 51 mov dx, 10 52 mov es, dx 53 mov ds, dx 54 mov ss, dx 55 ; ...far jump to load 32-bit code segment 56 jmp 18:7e00 57 58 59 a 200 60 ; // GDT // 61 db 1f, 00, 00, 7d, 00, 00, 00, 00 62 db 00, 00, 00, 00, 00, 00, 00, 00 63 db ff, ff, 00, 00, 00, 92, cf, 00 64 db ff, ff, 00, 00, 00, 9a, cf, 00 65 66 a 2fe 67 ; // signature for boot record // 68 db 55, aa 69 70 71 a 300 72 ;;;; finally, we produce the binary (3 sectors) ;;;; 73 74 n boot.bin 75 r cx 76 600 77 w 78 q 79 80
build.bat
1 @REM Copyright (c) 2010 the authors listed at the following URL, and/or 2 @REM the authors of referenced articles or incorporated external code: 3 @REM http://en.literateprograms.org/Hello_World_(IBM_PC_bootstrap)?action=history&offset=20081019141955 4 @REM 5 @REM Permission is hereby granted, free of charge, to any person obtaining 6 @REM a copy of this software and associated documentation files (the 7 @REM "Software"), to deal in the Software without restriction, including 8 @REM without limitation the rights to use, copy, modify, merge, publish, 9 @REM distribute, sublicense, and/or sell copies of the Software, and to 10 @REM permit persons to whom the Software is furnished to do so, subject to 11 @REM the following conditions: 12 @REM 13 @REM The above copyright notice and this permission notice shall be 14 @REM included in all copies or substantial portions of the Software. 15 @REM 16 @REM THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 17 @REM EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 18 @REM MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 19 @REM IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY 20 @REM CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, 21 @REM TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE 22 @REM SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 23 @REM 24 @REM Retrieved from: http://en.literateprograms.org/Hello_World_(IBM_PC_bootstrap)?oldid=15131 25 26 set OBJS=a.exe a.bin 27 set SRCS=crt0.s hello.c screen.c 28 set ARGS=-nostdlib -Wl,-Ttext -Wl,0x7e00 -Wl,-Tdata -Wl,0x7f00 29 30 del *.bin 31 gcc %ARGS% %SRCS% 32 objcopy -O binary a.exe a.bin 33 if not exist a.bin goto err 34 debug < boot.src 35 del %OBJS% 36 37 if not exist tail.img goto end 38 39 copy /b boot.bin + tail.img 144.img 40 del boot.bin 41 42 if not exist bochsrc.bxrc goto end 43 44 bochsrc.bxrc 45 goto end 46 47 :ERR 48 @echo off 49 echo - 50 echo - 51 echo gcc and objcopy failed or missing from PATH 52 pause 53 :END 54
crt0.s
1 xor %eax, %eax # boot sets CS,DS,ES,SS 2 mov %eax, %fs 3 mov %eax, %gs 4 5 mov $0x20000, %esp # set up a stack 6 call _rawmain # and enter the C code 7 8 wkbd: mov $0x64, %edx # if it returns, wait for any keypress 9 inb %dx, %al 10 andl $1, %eax 11 jz wkbd 12 13 mov $0x64, %edx # then reboot the machine 14 mov $0xfe, %eax 15 outb %al, %dx 16 17 cli 18 loop: jmp loop # (or at least hang) 19
hello.c
1 /* Copyright (c) 2010 the authors listed at the following URL, and/or 2 the authors of referenced articles or incorporated external code: 3 http://en.literateprograms.org/Hello_World_(IBM_PC_bootstrap)?action=history&offset=20081019141955 4 5 Permission is hereby granted, free of charge, to any person obtaining 6 a copy of this software and associated documentation files (the 7 "Software"), to deal in the Software without restriction, including 8 without limitation the rights to use, copy, modify, merge, publish, 9 distribute, sublicense, and/or sell copies of the Software, and to 10 permit persons to whom the Software is furnished to do so, subject to 11 the following conditions: 12 13 The above copyright notice and this permission notice shall be 14 included in all copies or substantial portions of the Software. 15 16 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 17 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 18 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 19 IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY 20 CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, 21 TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE 22 SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 23 24 Retrieved from: http://en.literateprograms.org/Hello_World_(IBM_PC_bootstrap)?oldid=15131 25 */ 26 27 extern void cls(), at(); 28 void rawmain() 29 { 30 cls(); 31 at(32,12,"Hello, world!"); 32 } 33
screen.c
1 /* Copyright (c) 2010 the authors listed at the following URL, and/or 2 the authors of referenced articles or incorporated external code: 3 http://en.literateprograms.org/Hello_World_(IBM_PC_bootstrap)?action=history&offset=20081019141955 4 5 Permission is hereby granted, free of charge, to any person obtaining 6 a copy of this software and associated documentation files (the 7 "Software"), to deal in the Software without restriction, including 8 without limitation the rights to use, copy, modify, merge, publish, 9 distribute, sublicense, and/or sell copies of the Software, and to 10 permit persons to whom the Software is furnished to do so, subject to 11 the following conditions: 12 13 The above copyright notice and this permission notice shall be 14 included in all copies or substantial portions of the Software. 15 16 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 17 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 18 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 19 IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY 20 CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, 21 TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE 22 SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 23 24 Retrieved from: http://en.literateprograms.org/Hello_World_(IBM_PC_bootstrap)?oldid=15131 25 */ 26 27 #define VIDEOMEM (char *)0xb8000 28 #define SCRX 80 29 #define SCRY 25 30 #define ATTRIB 0x71 /* blue on grey */ 31 32 void cls() 33 { 34 char *p = VIDEOMEM; 35 int n; 36 for(n = 0; n < SCRX*SCRY; ++n) { 37 *p++ = ' '; 38 *p++ = ATTRIB; 39 } 40 } 41 42 void at(int x, int y, char *m) 43 { 44 char *p = VIDEOMEM + 2*(x+SCRX*y); 45 while(*m) { 46 *p++ = *m++; 47 *p++ = ATTRIB; 48 } 49 } 50
