Mercurial > selfmade-os
changeset 1:42ba76f77035 default tip
the kernel with output and mem alloc
| author | meillo@marmaro.de |
|---|---|
| date | Sun, 01 Nov 2009 23:50:51 +0100 |
| parents | 99db6262c157 |
| children | |
| files | io.c io.h kernel.c makefile mem.c mem.h |
| diffstat | 6 files changed, 301 insertions(+), 0 deletions(-) [+] |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/io.c Sun Nov 01 23:50:51 2009 +0100 @@ -0,0 +1,151 @@ +#include <stdarg.h> +#include "io.h" + +void prints(const char* str); + +static unsigned short* vidmem = (unsigned short*) 0xb8000; +static unsigned short color = 0x0700; +static int pos = 0; + +void +cls(void) +{ + unsigned short* v; + + for (v = vidmem; v < vidmem+(80*25); v++) { + *v = 0; + } + pos = 0; +} + + +void +setcolor(int fg, int bg) +{ + color = (char) ((fg<<2) & (bg<<3)); +} + +void +setpos(int line, int col) +{ + pos = line * 80 + col; +} + +void +relpos(int move) +{ + pos += move; +} + + +void +printp(unsigned int n) +{ + int i, h; + char str[11]; + //int n = (int) p; + + str[0] = '0'; + str[1] = 'x'; + str[10] = '\0'; + for (i=9; i>1; i--) { + h = n % 16; + str[i] = ('0' + h); + if (h > 9) { + str[i] += 'a' - '9' - 1; + } + n /= 16; + } + prints(str); +} + + + + +void +printc(char c) +{ + putchar(c); +} + +void +prints(const char* str) +{ + const char* c; + + for (c = str; *c; c++) { + printc(*c); + } +} + +void +printd(int n) +{ + int i; + char str[32]; + + str[31] = '\0'; + for (i=30; i>0; i--) { + str[i] = ('0' + n%10); + if (n == 0) { + i++; + break; + } + n /= 10; + } + prints(&str[i]); +} + + +int +putchar(int c) +{ + if (c == '\n') { + pos = ((pos/80)+1) * 80; + } else { + vidmem[pos++] = (unsigned short)c | color; + } + return (unsigned char)c; +} + +int +puts(const char* s) +{ + prints(s); + putchar('\n'); + return 1; +} + +int +printf(const char* fmt, ...) +{ + va_list ap; + int i; + + va_start(ap, fmt); + for (i=0; fmt[i]; i++) { + if (fmt[i] != '%') { + printc(fmt[i]); + continue; + } + switch (fmt[++i]) { + case '%': + printc('%'); + break; + case 'c': + printc((char)va_arg(ap, int)); + break; + case 's': + prints(va_arg(ap, char*)); + break; + case 'd': + printd(va_arg(ap, int)); + break; + case 'p': + printp(va_arg(ap, unsigned int)); + break; + } + } + va_end(ap); + return 0; +}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/io.h Sun Nov 01 23:50:51 2009 +0100 @@ -0,0 +1,9 @@ + +void cls(void); +void setcolor(int fg, int bg); +void setpos(int line, int col); +void relpos(int move); + +int putchar(int c); +int puts(const char* s); +int printf(const char* fmt, ...);
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/kernel.c Sun Nov 01 23:50:51 2009 +0100 @@ -0,0 +1,31 @@ +/* markus schnalke <meillo@marmaro.de> */ + +#include "io.h" +#include "mem.h" + +void +kmain(void) +{ + unsigned char* p; + + cls(); + printf("OS says: Hi!\n\n"); + + initmem(0x00400000); /* heap starts at 4MB */ + + printf("init done\n"); + printf("\n"); + + p = malloc(28); + printf("allocated %d bytes at %p\n", 28, p); + p = malloc(15); + printf("allocated %d bytes at %p\n", 15, p); + + printf("aa %d bb %c cc %s\n", 5, '@', "hallo"); + printf("minmem: %p\n", 0x00400000); + + setpos(24, 0); + printf("loop\n"); + while (1) { + } +}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/makefile Sun Nov 01 23:50:51 2009 +0100 @@ -0,0 +1,28 @@ + +CC = i386-elf-gcc +CFLAGS = -Wall -Wextra -nostdlib -nostartfiles -nodefaultlibs + +LD = i386-elf-ld +LDFLAGS = -T linker.ld + +OBJ = loader.o kernel.o io.o mem.o + +qemu: os.iso + qemu -m 16 -boot cd -cdrom os.iso + +os.iso: kernel + cp kernel os-isofiles/boot/kernel + genisoimage -R -b boot/grub/stage2_eltorito -no-emul-boot -boot-load-size 4 -boot-info-table -o os.iso os-isofiles + +loader.o: loader.s + yasm -f elf -o loader.o loader.s + +kernel: linker.ld $(OBJ) + i386-elf-ld -T linker.ld -o kernel $(OBJ) + +clean: + rm -f *.o + rm -f kernel + +distclean: clean + rm -f os.iso
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mem.c Sun Nov 01 23:50:51 2009 +0100 @@ -0,0 +1,74 @@ +#include "mem.h" +#include "io.h" + + +void +initmem(unsigned int memstart) +{ + unsigned int* p; + int step = 2*1024*1024; + unsigned int* zero = 0x0; + + + minmem = (unsigned char*)memstart; + + /* disable cache */ + __asm__ __volatile__ ( + "movl %cr0, %eax\n\t" + "movl $0x60000000, %ebx\n\t" + "orl %ebx, %eax\n\t" + "movl %eax, %cr0" + ); + + /* test mem size */ + p = (unsigned int*) ((unsigned int)minmem/sizeof(char)); + do { + p += step; + *p = 0xf0f0f0f0; + } while (*p == 0xf0f0f0f0); + maxmem = (unsigned char*)p; + + /* test mem mirroring */ + p = 0; + *p = 0; + p++; + while (p < (unsigned int*)minmem) { + p = (unsigned int*) ((unsigned int)p * 2); + } + while (p < (unsigned int*)maxmem) { + *p = 0xf0f0f0f0; + if (*zero == 0xf0f0f0f0) { + maxmem = (unsigned char*)p; + break; + } + p = (unsigned int*) ((unsigned int)p * 2); + } + + /* enable cache again */ + __asm__ __volatile__ ( + "movl %cr0, %eax\n\t" + "movl $0x60000000, %ebx \n\t" + "negl %ebx\n\t" + "andl %ebx, %eax\n\t" + "movl %eax, %cr0" + ); + + /* min, max */ + printf("mem: start=%p end=%p size=%p\n", minmem, maxmem, (void*)(maxmem-minmem)); + + /* init heap */ + newp = minmem; +} + + +void* +malloc(unsigned int size) +{ + if (newp + size > maxmem) { + printf("Fatal error: memory exhausted!\n"); + while (1) { + } + } + newp += size; + return newp - size; +}