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December 10, 2023 08:38
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Enable/Disable hardware blinking provided by text mode on CGA/EGA/VGA cards
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;;;;;;;;;;;;;;;;;;;;;;;;; | |
;;;;; blink control ;;;;; | |
;;;;; CGA/EGA/VGA ;;;;; | |
; by Soha <soha@jin.sh> ; | |
; with MASM, 2023/12/09 ; | |
;;;;;;;;;;;;;;;;;;;;;;;;; | |
.model small | |
.stack | |
.data | |
no_ansi_prompt db "no ANSI.SYS or equivalent detected, please load it in CONFIG.SYS", 0dh, 0ah | |
db "$" | |
help db "Turn " | |
db 1bh, "[30;5;47m", "blinking text mode", 1bh, "[m" ; 5 for showing result | |
db " on/off on CGA/EGA/VGA cards.", 0dh, 0ah | |
db "Usage: BLINK.EXE [/]<1|0>", 0dh, 0ah | |
db "Author: Soha Jin <soha@jin.sh>", 0dh, 0ah | |
db "$" | |
log_cga db "CGA detected, $" | |
log_ega db "EGA/VGA detected, $" | |
log_ok db 1bh, "[1;37;5;41m" ; 5 for showing result | |
db " OK! " | |
db 1bh, "[m", 0dh, 0ah | |
db "$" | |
.code | |
print macro data | |
mov dx, seg data | |
mov ds, dx | |
lea dx, data | |
mov ah, 09h | |
int 21h | |
endm | |
commit: ; dl (0 = off, 1 = on) | |
mov ah, 12h | |
mov bl, 10h | |
int 10h | |
cmp bl, 4 ; BL is memory size enum, EGA/VGA should < 4 | |
mov bl, dl | |
ja commit_cga | |
jmp commit_bios | |
commit_bios: ; bl (0 = off, 1 = on), for EGA/VGA | |
print log_ega | |
mov ax, 1003h | |
xor bh, bh | |
int 10h | |
jmp committed | |
commit_cga: ; bl (0 = off, 1 = on), for CGA | |
print log_cga | |
mov ax, 40h ; BIOS | |
mov es, ax | |
mov dx, es:[63h] ; 40:0063 is the port address for 6845 chip | |
mov al, es:[65h] ; 40:0065 is the current value for MSR | |
add dx, 4 ; MSR (Mode Select Register) address | |
and al, 11011111b ; clr blink bit | |
test bl, bl | |
jz commit_cga_no_set | |
or al, 00100000b ; set blink bit | |
commit_cga_no_set: | |
out dx, al | |
mov es:[65h], al | |
committed: | |
print log_ok | |
ret | |
main proc | |
mov ax, 1a00h ; for ANSI.SYS | |
int 2fh ; MS-DOS Multiplex Interrupt | |
test al, al | |
jz no_ansi | |
xor bx, bx | |
mov bl, byte ptr ds:[80h] ; arg length | |
test bl, bl | |
jz usage | |
xor di, di | |
ckloop: mov ch, byte ptr ds:[81h+di] | |
cmp ch, 20h ; ' ' | |
je ckloop_inc | |
cmp ch, 2fh ; '/' | |
je ckloop_inc | |
sub ch, 30h | |
jmp ckloop_exit | |
ckloop_inc: inc di | |
cmp di, bx | |
jb ckloop | |
jmp usage | |
ckloop_exit: mov dl, ch | |
cmp dl, 1 | |
ja usage | |
call commit | |
jmp exit | |
no_ansi: | |
print no_ansi_prompt | |
jmp exit | |
usage: print help | |
exit: mov ax, 4c00h | |
int 21h | |
main endp | |
end main |
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Prebuilt EXE can be found here.
BLINK 0
disables blinking, can use 16 colors on background in text modeBLINK 1
enables blinking, can use 8 colors on background in text modeTested with CGA/EGA/VGA cards on 86Box (emulator) with 8088.
Tested with CGA (HD6845) and VGA (Cirrus Logic GD5429) cards on Book8088 (a laptop with 8088 made in 2023).
Tested with VGA (Chips & Technologies F65555) card on Toshiba Satellite Pro 480 CDT (a laptop with Pentium w/ MMX 233MHz).
There are more details in my blog (Chinese only).