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example1.asm
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Assembly Source File
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1993-09-26
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2KB
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92 lines
; 32BIT DOS EXTENDER
;
; Written by Adam Seychell Wed 8-25-1993
;
.386
DATA32 SEGMENT PUBLIC 'data' use32
CODE32_sel dw 50h ; Selector Values
CODE16_sel dw 58h
DATA_sel dw 60h
TheSTACK_sel dw 30h
VIDEO_sel dw 28h
FLAT_CODE32_sel dw 10h
FLAT_DATA_sel dw 08h
XMS_sel dw 18h
BASE_sel dw 20h
PSP_sel dw 48h
xms_usage dd 0 ; Requested size of XMS block in bytes.
xms_base dd ? ; Linear base address of the XMS block.
Base_Segment dw ? ; Real mode segment value for base memory.
PSP_segment dw ? ; Real mode segment value for PSP segment.
align 4
v86_mesg db ' Message printed in v86 mode ',10,13,36
DATA32 ENDS
CODE32 SEGMENT PUBLIC 'CODE' USE32
assume DS:DATA32 , CS:CODE32
include dos32.inc
start32: ; 32 bit code entry point. DS -> data descripor
mov es,[xms_sel] ;Must load these with valid selectors
mov fs,[FLAT_DATA_sel]
mov gs,[video_sel]
sti
; Example to call a real mode interrupt
mov SS:real_DS,DATA32 ; Set the DS reg for V86 mode
mov edx,offset v86_mesg
mov ah,9
dosint 21h
mov ah,4ch ; Termiate the program
int 21h
; The 16 hardware inetrrupts.
; If an IRQ accours in V86 mode the segment registers will contain same
; selector values as they were before the last V86 call. ( i.e dosint xx ).
IRQ0: dosint 08h ; 8253 Timer 0
iretd
IRQ1: dosint 09h ; 8242 Keyboard
iretd
IRQ2: dosint 0Ah ; LPT 2 or Vert Retrate (6845)
iretd
IRQ3: dosint 0Bh ; Serial communications ports 2 & 4
iretd
IRQ4: dosint 0Ch ; Serial communications ports 1 & 3
iretd
IRQ5: dosint 0Dh ; Reserved
iretd
IRQ6: dosint 0Eh ; NEC µPD765 Floppy Disk Controler
iretd
IRQ7: dosint 0Fh ; LPT 1
iretd
IRQ8: dosint 70h ; 6818 CMOS CLOCK
iretd
IRQ9: dosint 71h ; Reserved
iretd
IRQ10: dosint 72h ; Reserved
iretd
IRQ11: dosint 73h ; Reserved
iretd
IRQ12: dosint 74h ; Reserved
iretd
IRQ13: dosint 75h ; 80x87 Math Co-Pro exception.
iretd
IRQ14: dosint 76h ; Hard Drive Cotroller.
iretd
IRQ15: dosint 77h ; Reserved
iretd
CODE32 ENDS
END