From b41b6e23694394776e9b7e55632adef9eb075296 Mon Sep 17 00:00:00 2001 From: xamidev Date: Sun, 21 Dec 2025 14:56:19 +0100 Subject: [PATCH] Hello, world! in linear framebuffer --- Makefile | 6 ++- README.md | 7 ++++ src/kernel.h | 9 +++++ src/kmain.c | 13 ++++--- src/term.c | 99 ++++++++++++++++++++++++++++++++++++++++++++++++ src/term.h | 22 +++++++++++ zap-light16.psf | Bin 0 -> 5312 bytes 7 files changed, 149 insertions(+), 7 deletions(-) create mode 100644 src/kernel.h create mode 100644 src/term.c create mode 100644 src/term.h create mode 100644 zap-light16.psf diff --git a/Makefile b/Makefile index 92c59c1..56616ed 100644 --- a/Makefile +++ b/Makefile @@ -1,6 +1,7 @@ build: rm -f *.o - x86_64-elf-gcc -c -I src src/kmain.c -Wall -Wextra -std=gnu99 -nostdlib -ffreestanding -fno-stack-protector -fno-stack-check -fno-PIC -ffunction-sections -fdata-sections + x86_64-elf-gcc -c -I src src/term.c src/kmain.c -Wall -Wextra -std=gnu99 -nostdlib -ffreestanding -fno-stack-protector -fno-stack-check -fno-PIC -ffunction-sections -fdata-sections -mcmodel=kernel + objcopy -O elf64-x86-64 -B i386 -I binary zap-light16.psf zap-light16.o x86_64-elf-ld -o kernel -T linker.ld *.o limine/limine: @@ -25,5 +26,8 @@ build-iso: limine/limine build iso_root -o kernel.iso ./limine/limine bios-install kernel.iso +run: + qemu-system-x86_64 -cdrom kernel.iso + clean: rm -rf *.o kernel iso_root kernel.iso limine diff --git a/README.md b/README.md index dacc5de..518f056 100644 --- a/README.md +++ b/README.md @@ -9,3 +9,10 @@ make build-iso ``` Then it can be run with `qemu-system-x86_64 kernel.iso`. + + +### Kernel conventions + +Functions that return an integer as status of success/failure will return: +- 0 if everything went correctly +- a negative value if something went wrong diff --git a/src/kernel.h b/src/kernel.h new file mode 100644 index 0000000..918fa6a --- /dev/null +++ b/src/kernel.h @@ -0,0 +1,9 @@ +#ifndef KERNEL_H +#define KERNEL_H + +enum ErrorCodes +{ + ENOMEM +}; + +#endif diff --git a/src/kmain.c b/src/kmain.c index 2f35998..3c321eb 100644 --- a/src/kmain.c +++ b/src/kmain.c @@ -1,6 +1,7 @@ #include #include #include +#include "term.h" // Limine version used __attribute__((used, section(".limine_requests"))) @@ -19,6 +20,8 @@ static volatile LIMINE_REQUESTS_START_MARKER; __attribute__((used, section(".limine_requests_end"))) static volatile LIMINE_REQUESTS_END_MARKER; +struct limine_framebuffer* framebuffer; + // We won't be linked to standard library, but still need the basic mem* functions // so everything goes allright with the compiler @@ -103,14 +106,12 @@ void kmain() if (framebuffer_request.response == NULL || framebuffer_request.response->framebuffer_count < 1) hcf(); // Get the first framebuffer from the response - struct limine_framebuffer* framebuffer = framebuffer_request.response->framebuffers[0]; + framebuffer = framebuffer_request.response->framebuffers[0]; + + if (term_init()) hcf(); // Draw something - for (size_t i=0; i<100; i++) - { - volatile uint32_t* fb_ptr = framebuffer->address; - fb_ptr[i*(framebuffer->pitch/4) + i] = 0xffffff; - } + kputs("Hello, world!"); hcf(); } diff --git a/src/term.c b/src/term.c new file mode 100644 index 0000000..dd1e397 --- /dev/null +++ b/src/term.c @@ -0,0 +1,99 @@ +// Terminal output + +#include +#include +#include "kernel.h" +#include "term.h" + +extern struct limine_framebuffer* framebuffer; + +// Importing the PSF object file +extern unsigned char _binary_zap_light16_psf_start[]; +extern unsigned char _binary_zap_light16_psf_end[]; + +PSF1_Header* font = (PSF1_Header*)_binary_zap_light16_psf_start; +uint8_t* glyphs = _binary_zap_light16_psf_start + sizeof(PSF1_Header); + +#define FONT_WIDTH 8 +#define FONT_HEIGHT font->characterSize + +// Character cursor +typedef struct +{ + unsigned int x; + unsigned int y; +} Cursor; + +Cursor cursor = {0}; + +unsigned char* fb; + +int term_init() +{ + // Get framebuffer address from Limine struct + + if (framebuffer) + { + fb = framebuffer->address; + return 0; + } + return -ENOMEM; +} + +// These are marked "static" because we don't wanna expose them all around +// AKA they should just be seen here (kind of like private functions in cpp) +static void putpixel(int x, int y, int color) +{ + // Depth isn't part of limine_framebuffer attributes so it will be 4 + unsigned pos = x*4 + y*framebuffer->pitch; + fb[pos] = color & 255; // blue channel + fb[pos+1] = (color >> 8) & 255; // green + fb[pos+2] = (color >> 16) & 255; // blue +} + +static void draw_char(char c, int px, int py, int fg, int bg) +{ + uint8_t* glyph = glyphs + ((unsigned char)c * FONT_HEIGHT); + + for (size_t y=0; y> x)) ? fg : bg; + putpixel(px+x, py+y, color); + } + } +} + +static void putchar(char c) +{ + if (c == '\n') + { + cursor.x = 0; + cursor.y++; + return; + } + + if ((cursor.x+1)*FONT_WIDTH >= framebuffer->width) + { + cursor.x = 0; + cursor.y++; + } + + int px = cursor.x * FONT_WIDTH; + int py = cursor.y * FONT_HEIGHT; + draw_char(c, px, py, WHITE, BLACK); + cursor.x++; +} + +// Debug-printing +void kputs(const char* str) +{ + unsigned int i=0; + while (str[i] != 0) + { + putchar(str[i]); + i++; + } +} \ No newline at end of file diff --git a/src/term.h b/src/term.h new file mode 100644 index 0000000..c7bcf5c --- /dev/null +++ b/src/term.h @@ -0,0 +1,22 @@ +#ifndef TERM_H +#define TERM_H + +int term_init(); +void kputs(const char* str); + +enum TermColors +{ + BLACK = 0x000000, + WHITE = 0xffffff +}; + +#define PSF1_FONT_MAGIC 0x0436 + +typedef struct +{ + uint16_t magic; + uint8_t fontMode; + uint8_t characterSize; // height +} PSF1_Header; + +#endif diff --git a/zap-light16.psf b/zap-light16.psf new file mode 100644 index 0000000000000000000000000000000000000000..047bd1b0be57f5165922969887fd5c6b3ede3304 GIT binary patch literal 5312 zcmZvfYj|8m8ONumYuWPTX}2NR#ja$!-P22gWqTn_!x}b+CGLjWrV9ZrErg^*Q7#pg zR#-M)dH5vt6W^#dDpo?=ZroX2GPqlk>dUR5~-O%TA{=x~wy4)o?nKPI)+}R{f?) z&a6~suyM9AC~c84#mtiKRJwcR*kaFX>CDQSms*V8lP)g2tIeL4q?CK8LP3I@JEhY_ zrOv~1*m$S+7`IpwMUvC_SREWZSj}YmCMF)R`sEuYw%fO4UaQ5L8DRXa#0)TglbE^g zmO;_qLbYAD-a9RwH8UC72ui9H1m*J9AmEiG`Oqk8bjb695`%DqWmr+{tR247Qoq>c zQQyoDP9<9q>!_Z6+RAC>Ni@Ccm~jf&AhJh{Kke44)!~H;Yi>r@jg4(gr(eHj&8Ur+ z#WTD5s$g`pXrjBBvR0L%z@&6KB}JNHo0Q3D=aR1V<@#!^3CBDO&Kf-^X+>^ErLAXF z!Shn4O|7ks`3c7A(frcG>}o=hTJtB{TbEr-{Jk7=Z`VVqR98=-Qfa1Aru#}Y%jI&z zlf|*|a~e(fNH?PnxZXekizj(MF#JX(l zrhdGi+0i7^oNKRhKld`Tq)NrjM^LGbPfm_kE6!h zY;1JY`P05lZhh?7BtqOjvG15E%{K*NZ&WLcGPb+(WVLKXo2<6M$z6OplF#RRdZP71 z*J=|J)6-G^0?vn-bX#BCaVA+U`$e{&o6np*Et2PqgEl87mGV3z2W?*@mkCSvb;Qr5l~yHw)5cNLR5TS)5lTaua| zfkb^oLeom`>T0!FC2g}!vO8olnSaJX`|qn)VZ#_7a-0d$y7d0PRX8S=tT05BJG{L3d@Z8+tN9Jri znZ!hr9h)d%=;rG}Zb#B!C6(3XR{Q8da}gOUbvy27itUQb?66nH@I9oV^GT+L$)da6 zjz4j}GsSVaQDWc0iv04mv=|tD>#K4TYqM1rXj4>YpjO+)dddC5e(&55+{1iYmD}z= z{6bf^{Wg*JDCA;ii1g_WNBMG>6cwMgGS*T3*xnH@j12DC*`LUMe?Iva`MKugagHKu zJ%=GG3Zq&*9m&P*%`CMBr_ZELCLEV$dacEko=lxd=%rEp*zW4Pc%eF#hAbgoaP&Bd~d(3fjzmC>_0{`JKzojRLxW-c5~Tua z+kL>4q;oR9_U{GPKRMFI?)n#N*S}axeRtyo4nH zgg)-itn~X=^@rh66^6&)%kWY7ID85A&kIAX!*DqiA-_BfSMuBpLy*(GdVuE}^%3ty z?o?-xU`HVjABKIfr`&y-Z*XuA`P1zdgQ(N^?#?;UICF+Ft25fIqpX7ur(cSt2 zeWmWkx>gk^zf@K9g{UIF>tH=>fQ@h&48SHBgv~Id2JpU|w-UTrl^NYIZ&yGWMj(JI zp#oRID7*!#P=hhJTJDgphil+kn1JixdUzYW9d^JCuv5LdCJcA+ zcB6XIJMPV2!Hl9N)f3(^?^!Ram+8xN7~V|T6imZzxCLh59q>-L72XB!hTGtFxC8El zJ@6j53*HOwgZIPTuow2h2jCvK7aD2>GjtzsP4$Au%IS;pCwz7wC0~QD!#ChbcuMs% z3&(l;CVUH?hG*be_%?h8o`VzcU6o4#7cq3?5fcGn!AS=gB{f{tSE;?xW7< z)ltsZ7f@eRtMpU(b?k~J<%cOb0#864eGTk`ub`FRqc7Btvtk~->hfn|q1-oJo+hrg73m%ogB(qBP7 z?e~+<_#4P?^)DyC&A*!bet2+s7=8#o2>anz^z_&88~82!4t@`RfIq^Y;Lq?E_$&Mk m{thp}Kj5G6GQ0x+f|Kwn{2NZeY4{KP7ybul;59f4A^aazON1E! literal 0 HcmV?d00001