From: phfr24 Date: Mon, 15 Dec 2025 22:43:26 +0000 (-0300) Subject: cleanup X-Git-Url: https://git.wirehaze.ovh/lifeboot.git/commitdiff_plain/58bca448272b36192954e96b0b060f9c245b603b?hp=a8cfbb9937178d02aa35816ac8607b2525ba7263 cleanup --- diff --git a/.gitignore b/.gitignore index 956b27b..ad88f04 100644 --- a/.gitignore +++ b/.gitignore @@ -1,6 +1,2 @@ **/.*.swp **/*.bin -**/*.o -**/a.out -prototype -lifeboot diff --git a/Makefile b/Makefile index 3117265..c3f5556 100644 --- a/Makefile +++ b/Makefile @@ -1,20 +1,14 @@ -SRC_DIR := . -PROGRAMS := prototype lifeboot -CC := gcc -CFLAGS := -Wall -Wextra -I. +SRC := lifeboot.asm +BIN := boot.bin +QEMU := qemu-system-i386 -lifeboot: lifeboot.asm - nasm lifeboot.asm +$(BIN): $(SRC) + nasm $(SRC) -f bin -o $(BIN) -all: $(PROGRAMS) - -run: lifeboot - qemu-system-x86_64 -drive file=lifeboot,format=raw - -format: - find $(SRC_DIR) -iname '*.[hc]' | xargs clang-format -i --style=GNU +run: $(BIN) + $(QEMU) -drive file=$(BIN),format=raw clean: - rm -rf $(PROGRAMS) *.o + rm -f $(BIN) -.PHONY: all run format clean +.PHONY: run clean diff --git a/lifeboot.asm b/lifeboot.asm index 9b03696..d4ba435 100644 --- a/lifeboot.asm +++ b/lifeboot.asm @@ -8,13 +8,13 @@ org 7c00h %define DEAD ' ' ; char to represent a dead cell %define ALIVE '.' ; char to represent an alive cell %define PRINT_COLOR 07h ; grey on black -%define ITER_LIM 500 ; reset the simulation after ITER_LIM iterations +%define ITER_LIM 500 ; reset the simulation after this # iterations ; constants ------------------------------------------------------------------- %define COLS 80 %define ROWS 25 -%define VGAPGSZ 1000h +%define VGAPGSZ 1000h ; (bytes) ; memory layout --------------------------------------------------------------- @@ -32,13 +32,15 @@ org 7c00h ; entry point ----------------------------------------------------------------- +entry: + ; initialize segment registers mov ax, VGA >> 4 -mov es, ax +mov es, ax ; es:0 -> video memory xor ax, ax -mov ds, ax -mov ss, ax +mov ds, ax ; ds = 0 +mov ss, ax ; ss = 0 ; set stack pointers mov bp, ORG @@ -50,19 +52,17 @@ cld ; disable cursor mov ch, 3fh ; cursor start and options mov ah, 01h ; set text-mode cursor shape -int 10h ; video services +int 10h ; bios video services ; initialize xss +.set_xss: + mov ah, 00h ; get system time + int 1ah ; bios time services + ; cx:dx = # clock ticks since midnight + or dx, dx + jz .set_xss ; wait for something meaningful -set_xss_seed: - -mov ah, 00h ; get -int 1ah ; system time - -cmp dx, 0 -je set_xss_seed ; if seed is 0, xs wont work properly - -mov [xss], dx ; cx:dx = number of clock ticks since midnight +mov [xss], dx ; initialize currvgapg mov word [currvgapg], 0 @@ -72,21 +72,19 @@ mov word [currvgapg], 0 start: call init_grid -mov word [iter], 1 +mov word [iter], 0 -; apply game of life's rules to determine the next state ---------------------- +.next_state: -next_state: + call vsync_wait + call update_grid -call vsync_wait -call write_next_vga_page + call vsync_wait + call flip_vgapg -call vsync_wait -call flip_vga_page - -inc word [iter] -cmp word [iter], ITER_LIM -jle next_state + inc word [iter] + cmp word [iter], ITER_LIM + jl .next_state jmp start ; reset @@ -94,23 +92,23 @@ jmp start ; reset ; functions ------------------------------------------------------------------- -; vsync_wait() - wait for display to enter the next VBlank cycle -------------- +; vsync_wait() - wait for display to enter the next retrace cycle ------------- -; clobbers ax, dx +; clobbers al, dx vsync_wait: mov dx, 3dah ; input status #1 register -.wait_on: +.wait_retrace_end: in al, dx test al, 08h ; vertical retrace bit - jnz .wait_on + jnz .wait_retrace_end -.wait_off: +.wait_retrace_start: in al, dx test al, 08h - jz .wait_off + jz .wait_retrace_start ret @@ -118,6 +116,7 @@ ret ; output: ; [xss] = updated state +; bx = [xss] ; clobbers bx, dx @@ -151,36 +150,39 @@ mov di, [currvgapg] ; es:di -> grid start mov cx, COLS * ROWS ; for each cell .write_cell: ; do { - call xs ; [xss] = rand + call xs ; bx = random value mov al, DEAD ; al = DEAD (likely) - test word [xss], 0b11 + test bx, 0b11 - jnz .nz ; if ([xss] % 4 == 0) + jnz .nz ; if (bx % 4 == 0) mov al, ALIVE ; al = ALIVE .nz: - stosw ; [es:di] = ax ; di += 2 + stosw ; [es:di] = ax, di += 2 loop .write_cell ; } while (--cx) ret -; flip_vga_page() - flip active display page ---------------------------------- +; flip_vgapg() - flip active display page ------------------------------------- + +; output: +; [currvgapg] ^= VGAPGSZ -; clobbers ax, dx +; clobbers ax -flip_vga_page: +flip_vgapg: -xor word [currvgapg], VGAPGSZ ; flip currvgapg -setnz al ; al = !(currvgapg == 0) +xor word [currvgapg], VGAPGSZ +setnz al ; al = !(currvgapg == 0) mov ah, 05h ; select active display page -int 10h ; video services +int 10h ; bios video services ret -; alive_neighbours() ---------------------------------------------------------- +; alive_neighbours() - get number of alive adjacent cells --------------------- ; input: ; es:si -> current grid @@ -202,7 +204,7 @@ enter 5, 0 mov ax, cx ; ax = idx mov bl, COLS ; bl = COLS -div bl ; al = idx / COLS ; ah = idx % COLS +div bl ; al = idx / COLS, ah = idx % COLS mov [bp - 1], al ; row = idx / COLS mov [bp - 2], ah ; row = idx % COLS @@ -215,26 +217,26 @@ mov byte [bp - 4], -1 ; i = -1 .j: ; do { mov al, [bp - 4] - or al, [bp - 5] - jz .continue ; if (!i && !j) continue + or al, [bp - 5] ; if (!i && !j) + jz .continue ; continue mov al, [bp - 1] add al, [bp - 4] ; al = row + i - cmp al, 0 - jl .continue ; if (row + i < 0) continue + cmp al, 0 ; if (row + i < 0) + jl .continue ; continue - cmp al, ROWS - jge .continue ; if (row + i >= ROWS) continue + cmp al, ROWS ; if (row + i >= ROWS) + jge .continue ; continue mov ah, [bp - 2] add ah, [bp - 5] ; ah = col + j - cmp ah, 0 - jl .continue ; if (col + j < 0) continue + cmp ah, 0 ; if (col + j < 0) + jl .continue ; continue - cmp ah, COLS - jge .continue ; if (col + j >= COLS) continue + cmp ah, COLS ; if (col + j >= COLS) + jge .continue ; continue movzx bx, ah ; bx = col + j @@ -246,8 +248,8 @@ mov byte [bp - 4], -1 ; i = -1 mov dx, [es:si + bx] ; dl = cell state - cmp dl, ALIVE ; if (!ALIVE) continue - jne .continue + cmp dl, ALIVE ; if (!ALIVE) + jne .continue ; continue inc byte [bp - 3] ; neighbours++ @@ -265,7 +267,7 @@ movzx ax, byte [bp - 3] ; ax = # alive neighbours leave ret -; write_next_cell_state() ----------------------------------------------------- +; update_cell() - write next cell state --------------------------------------- ; input: ; es:si -> current grid @@ -277,7 +279,7 @@ ret ; clobbers ax, bx, dx -write_next_cell_state: +update_cell: call alive_neighbours ; ax = # alive neighbours @@ -314,25 +316,25 @@ mov [es:di + bx], dx ret -; write_next_vga_page() ------------------------------------------------------- +; update_grid() - write next grid (inactive vga page) ------------------------- ; clobbers di, si, ax, bx, cx, dx -write_next_vga_page: +update_grid: mov si, [currvgapg] ; es:si -> current page mov di, VGAPGSZ xor di, si ; es:di -> next page -xor cx, cx ; i = 0 +mov cx, COLS * ROWS - 1 ; for each cell (index) + +.update_loop: ; do { -.update_loop: -call write_next_cell_state + call update_cell -inc cx -cmp cx, COLS * ROWS -jl .update_loop ; for i in [0 .. COLS * ROWS - 1] + dec cx + jns .update_loop ; } while (--cx > 0) ret diff --git a/prototype.c b/prototype.c deleted file mode 100644 index 83b9398..0000000 --- a/prototype.c +++ /dev/null @@ -1,134 +0,0 @@ -#include -#include -#include -#include - -#define COLS 80 -#define ROWS 25 - -#define DEAD ' ' -#define ALIVE '#' - -#define INIT_RATIO 4 - -#define STR(x) _STR (x) -#define _STR(x) #x - -static uint16_t xss; /* xs() state */ - -static uint16_t -xs () /* xorshift prng */ -{ - xss ^= (xss << 1); - xss ^= (xss >> 3); - xss ^= (xss << 10); - - return xss; -} - -static void -clearscr () -{ - printf ("\e[1;1H\e[2J"); -} - -static void -print_row (char row[COLS]) -{ - printf ("%." STR (COLS) "s\n", row); -} - -static void -print_grid (char grid[COLS * ROWS]) -{ - for (int i = 0; i < ROWS; i++) - print_row (grid + i * COLS); -} - -static void -init_grid (char grid[COLS * ROWS]) -{ - for (int i = 0; i < COLS * ROWS; i++) - { - if (xs () % INIT_RATIO) - grid[i] = DEAD; - else - grid[i] = ALIVE; - } -} - -static char -get_state (char grid[COLS * ROWS], int row, int col) -{ - if (row < 0 || row >= ROWS || col < 0 || col >= COLS) - return DEAD; - - return grid[row * COLS + col]; -} - -static int -alive_neighbours (char grid[COLS * ROWS], int idx) -{ - int row = idx / COLS; - int col = idx % COLS; - int neighbours = 0; - - for (int i = -1; i <= 1; i++) - for (int j = -1; j <= 1; j++) - if (get_state (grid, row + i, col + j) == ALIVE) - neighbours++; - - if (get_state (grid, row, col) == ALIVE) - neighbours--; - - return neighbours; -} - -static char -next_state (char grid[COLS * ROWS], int idx) -{ - int n = alive_neighbours (grid, idx); - - if (get_state (grid, idx / COLS, idx % COLS) == ALIVE) - { - if (n < 2 || n > 3) - return DEAD; - - return ALIVE; - } - - if (n == 3) - return ALIVE; - - return DEAD; -} - -static void -update_grid (char grid[COLS * ROWS]) -{ - char new[COLS * ROWS]; - - for (int i = 0; i < COLS * ROWS; i++) - new[i] = next_state (grid, i); - - memcpy (grid, new, COLS * ROWS); -} - -int -main () -{ - char grid[COLS * ROWS]; - - xss = time (0); - init_grid (grid); - - do - { - clearscr (); - print_grid (grid); - update_grid (grid); - } - while (getchar () != 'q'); - - return 0; -}