Web1. When two bytes are multiplied −. The multiplicand is in the AL register, and the multiplier is a byte in the memory or in another register. The product is in AX. High-order 8 bits of the product is stored in AH and the low-order 8 bits are stored in AL. 2. When two one-word values are multiplied −. WebSep 30, 2024 · If that fails, we try the most traditional approach of sending a write command (0xD1), followed by an A20-enabling command (0xDF) to the keyboard controller. 0x64 represents the controller's command register only for writing, while 0x60 is a data port for both reading and writing.
lll/stage1.s at main · leap0x7b/lll · GitHub
Webout 0x64, al: waitfree2: in al, 0x64 and ax, byte 2: jnz waitfree2: mov al, 0xDF: out 0x60, al: lgdt[info_gdt] ;carico la gdt: mov eax,cr0 ; metto in eax cr0: or al,1 ; imposto bit per pmode: mov cr0,eax ; entro in modalita protetta: jmp dword (gdt_code-gdt_table):pmode ; tutto e' pronto, e quindi eseguo il codice a 32 bit WebJul 31, 2009 · out 0x64,al ; Output command to keyboard l.6: in al,0x64 test al,2 jnz l.6 ; Wait 'till buffer is empty again mov al,0xDF ; keyboard: set A20 out 0x60,al ; Send it to the keyboard controller mov cx,14h l.7: ; this is approx. a 25uS delay to wait ... iplayer numberblocks number 4
linux-0.12/setup.S at master · ultraji/linux-0.12 · GitHub
WebNov 16, 2024 · in al, 0x64 test al, 0x02 jnz check_A20 mov al, 0xDF out 0x60, al mov si, msg_Load call print_string_16 mov cx, 0x4000 - 1 ; Start looking from here VBESearch: inc cx cmp cx, 0x5000 je halt mov edi, VBEModeInfoBlock ; VBE data will be stored at this address mov ax, 0x4F01 ; GET SuperVGA MODE INFORMATION - http://www.ctyme.com/intr/rb … WebDec 17, 2024 · in al, 0x64 test al, 0x2 jnz seta20.2 # 0xdf -> port 0x60 mov al, 0xdf out 0x60, al # Switch from real to protected mode. Use a bootstrap GDT that makes # virtual … WebMar 24, 2005 · ;;;; Enable the A20 line.;;=====; enable_A20: pusha cli ; Disable all irqs cld mov al, 255; Mask all irqs out 0xa1, al out 0x21, all.5: in al, 0x64; Enable A20 test al, 2; Test the buffer full flag jnz l.5 ; Loop until buffer is empty mov al, 0xD1; Keyboard: write to output port out 0x64, al ; Output command to keyboard l.6: in al, 0x64 test al ... oratory school woodcote