tables.8

PC x386 bios source code

        ;
        ; initialization tables
        ;
        ; (C)1997-2001 Pascal Dornier / PC Engines; All rights reserved.
        ; This file is licensed pursuant to the COMMON PUBLIC LICENSE 0.5.
        ;

        ;
        ; Initial initialization table (used in post2)
        ;
clrtab: db      cm_nmi+cm_b,cm_idx      ;RTC: disable NMI
        db      2,cm_dat        ;RTC: BCD mode, interrupt disable
        db      cm_nmi+cm_a,cm_idx      ;RTC: 32768 Hz oscillator, 1ms int
        db      26h,cm_dat

        db      4,dma0+8        ;disable dma0
        db      4,dma1+8+8      ;disable dma1
        db      0,dma0+0dh      ;reset dma0 (data don't care)
        db      0,dma1+0dh+0dh  ;reset dma1 (data don't care)
        db      0fh,dma0+0fh    ;mask all channels
        db      0fh,dma1+0fh+0fh        ;mask all channels
        db      0,dma0+8        ;Enable dma0
        db      0,dma1+8+8      ;Enable dma1

        db      0fch,port61     ;disable parity

#if def NO_ISAREF
        db      50h,timer+3
#else
        db      54h,timer+3     ;init refresh
#endif
        db      12h,timer+1     ;refresh interval

        db      0ffh,0ffh       ;end of table
        ;
        ; Timer, DMA, PIC initialization table (used in post2)
        ;
        ; first data byte, then port address
        ;
tdmatab:        db      0,dma1+8+8      ;Enable dma1
        db      0c0h,dma1+0bh+0bh       ;Cascade mode, channel 4
        db      041h,dma1+0bh+0bh       ;Single mode, channel 5
        db      042h,dma1+0bh+0bh       ;Single mode, channel 6
        db      043h,dma1+0bh+0bh       ;Single mode, channel 7
        db      0,dma1+09h+09h  ;clear DRQ4 request
        db      0,dma1+0ah+0ah  ;unmask DRQ4 -> enable cascade
        db      0,dma0+8        ;Enable dma0
        db      40h,dma0+0bh    ;Single mode, channel 0
        db      41h,dma0+0bh    ;Single mode, channel 1
        db      42h,dma0+0bh    ;Single mode, channel 2
        db      43h,dma0+0bh    ;Single mode, channel 3

        db      0,npx+1 ;clear x87 interrupt

        db      11h,pic0        ;ICW1: edge, ICW4
        db      08h,pic0+1      ;ICW2: interrupt vector 08..0F
        db      04h,pic0+1      ;ICW3: IRQ2 is used for cascade
        db      01h,pic0+1      ;ICW4: 8086 mode
        db      0ffh,pic0+1     ;OCW: mask all interrupts

        db      11h,pic1        ;ICW1: edge, ICW4
        db      70h,pic1+1      ;ICW2: interrupt vector 70..77
        db      02h,pic1+1      ;ICW3: slave identification number
        db      01h,pic1+1      ;ICW4: 8086 mode
        db      0ffh,pic1+1     ;OCW: mask all interrupts

        db      26h,port92      ;enable A20 gate

        db      0ffh,0ffh       ;end of table
        ;
        ; baud rates, H/L swapped
        ;
rs_baud:        db      04,17h  ;110 baud
        db      03,00h  ;150 baud
        db      01,80h  ;300 baud
        db      00,0c0h ;600 baud
        db      00,60h  ;1200 baud
        db      00,30h  ;2400 baud
        db      00,18h  ;4800 baud
        db      00,0ch  ;9600 baud
        ;
        ; serial port I/O addresses (points to scratch register)
        ;
rs_ports:       dw      3ffh,2ffh,3efh,2efh,287h,28fh
        dw      297h,29fh,2F7h,377h,0   ;0 = end of table
        ;
        ; parallel port I/O addresses
        ;
lp_ports:       dw      03bch,0378h,0278h,0     ;0 = end of table
        ;
        ; RTC initialization table
        ;
        ; Note: When location cm_dia is set to 80, MS-DOS will ignore the
        ; RTC date and set 1980.
        ;
rtc_tab:
        db      0,cm_ss ;00: second
        db      0,cm_ssa        ;01: alarm second
        db      0,cm_mm ;02: minute
        db      0,cm_mma        ;03: alarm minute
        db      0,cm_hh ;04: hour
        db      0,cm_hha        ;05: alarm hour
        db      0,cm_day        ;06: day of week
        db      1,cm_dd ;07: day
        db      1,cm_mo ;08: month
        db      00h,cm_yy       ;09: year
        db      80h,cm_dia      ;0E: power loss flag
        db      20h,cm_cent     ;32: century
rtc_tab9:                       ;end of table