works nicely from the floppy

[bootsplash] / bootsplash.asm

diff --git a/bootsplash.asm b/bootsplash.asm
index 5885c4d..b7f53c7 100644 (file)
--- a/bootsplash.asm
+++ b/bootsplash.asm
@@ -1,13 +1,26 @@
        org 7c00h
        bits 16
 
+BOOT_DEV equ 80h
+
 stacktop equ 7b00h
 boot_driveno equ 7b00h ; 1 byte
 stage2_size equ stage2_end - stage2_start
 
-spawn_rate equ 256
+spawn_rate equ 512
 framebuf equ 40000h
 
+%macro floppy_motor_off 0
+       pushf
+       and dl, 80h
+       jnz %%end       ; skip if high bit is set (i.e. it's not a floppy)
+       mov dx, 3f2h
+       in al, dx
+       and al, 0fh
+       out dx, al
+%%end: popf
+%endmacro
+
 start:
        xor ax, ax
        mov ds, ax
@@ -23,12 +36,13 @@ start:
        xor ax, ax
        mov es, ax
        mov bx, stage2_start
-       mov ah, 2               ; read sectors LBA call
+       mov ah, 2               ; read sectors call
        mov al, (stage2_size + 511) / 512  ; num sectors
        mov cx, 2               ; ch: cylinder, cl: sector
        xor dx, dx              ; dh: head
        mov dl, [boot_driveno]
        int 13h
+       floppy_motor_off        ; turn off floppy motor (if dl is < 80h)
        jnc stage2_start        ; loaded successfully, jump to it
 
        ; failed to load second sector
@@ -52,15 +66,19 @@ printstr:
 .done: ret
 
 str_load_fail db "Failed to load second stage!",0
-str_booting db "Booting ...",0
+str_booting db "Booting system... ",0
+str_bootfail db "failed!",0
 
 
        times 510-($-$$) db 0
-       dw 0xaa55
+bootsig dw 0xaa55
 
        ; start of the second stage
 stage2_start:
+       pushf
+       cli
        call splash
+       popf
 
        xor ax, ax
        mov es, ax
@@ -69,10 +87,39 @@ stage2_start:
        mov ax, str_booting
        call printstr
 
-       cli
-.hang: hlt
+       ; blank out the existing boot signature to really see if a boot sector
+       ; gets loaded correctly
+       xor ax, ax
+       mov [bootsig], ax
+
+       ; load from BOOT_DEV into 7c00h and jump
+       mov bx, 7c00h
+       mov ax, 0201h           ; ah: call 2 (read sectors), al: count = 1
+       mov cx, 1               ; ch: cylinder 0, cl: sector 1
+       mov dx, BOOT_DEV        ; dh: head 0, dl: boot device number
+       int 13h
+       floppy_motor_off        ; turn floppy motor off (if dl < 80h)
+
+       jc .fail                ; BIOS will set the carry flag on failure
+       mov ax, [bootsig]
+       cmp ax, 0aa55h
+       jnz .fail               ; fail if what we loaded is not a valid boot sect
+
+       mov ax, 0e0dh
+       mov bx, 7
+       int 10h
+       mov ax, 0e0ah
+       int 10h
+
+       jmp 7c00h               ; all checks passed, jump there
+
+.fail: mov ax, str_bootfail
+       call printstr
+.hang: cli
+       hlt
        jmp .hang
 
+
        ; splash screen effect
 splash:
        mov ax, 13h
@@ -142,6 +189,15 @@ splash:
        xor edx, edx
        div dword [num_spawn_pos]       ; edx <- rand % num_spawn_pos
        mov bx, [es:edx * 2]            ; grab one of the spawn positions
+
+       ; animate the spawn position
+       xor ax, ax
+       mov al, [frameno]
+       mov bp, ax
+       movsx ax, byte [bp + sintab]
+       sar ax, 3
+       add bx, ax
+
        mov byte [fs:bx], 0xff          ; plot a pixel there
        dec cx
        jnz .spawn
@@ -153,13 +209,23 @@ splash:
        xor ax, ax      ; use: pixel accum
        xor dx, dx      ; use: second pixel
 .blurloop:
+       xor ax, ax
        mov al, [bx]
        mov dl, [bx + 320]
        add ax, dx
-       shr ax, 1
+       mov dl, [bx + 319]
+       add ax, dx
+       mov dl, [bx + 321]
+       add ax, dx
+       mov dl, [bx + 640]
+       add ax, dx
+       xor dx, dx
+       mov cx, 5
+       div cx
        mov [bx], al
+
        inc bx
-       cmp bx, 64000 - 320 * 2
+       cmp bx, 64000 - 640
        jnz .blurloop
 
 
@@ -184,6 +250,8 @@ splash:
        xor ax, ax
        mov ds, ax
 
+       inc word [frameno]
+
        ; check for keypress
        in al, 64h
        and al, 1
@@ -240,7 +308,10 @@ randval dd 0ace1h
 
 
        ; data
+%include "lut.inc"
+
 num_spawn_pos dd 0
+frameno dw 0
        align 16
 spawn_pos:
 imgrle:        incbin "nuclear.rle"