Implement date/time
This commit is contained in:
Juhani Krekelä
parent
68030372b7
commit
b9c83b11cd
1 changed files with 145 additions and 18 deletions
163
io.asm
163
io.asm
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@ -22,7 +22,7 @@ data ends
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iogroup group code, constants, data
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code segment
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assume cs:iogroup, ds:iogroup, es:iogroup
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assume cs:iogroup
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org 0
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; Jump table
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@ -36,9 +36,9 @@ jmp unimplemented ; 0012 Serial write
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jmp near ptr diskread ; 0015
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jmp diskwrite ; 0018
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jmp near ptr diskchange ; 001b
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jmp setdate ; 001e
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jmp settime ; 0021
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jmp gettime ; 0024
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jmp near ptr setdate ; 001e
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jmp near ptr settime ; 0021
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jmp near ptr gettime ; 0024
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jmp near ptr flush ; 0027
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jmp near ptr mapdev ; 002a
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@ -99,11 +99,11 @@ init:
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int 10h
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; Set random record field 0
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mov word ptr command_fcb+33, 0
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mov word ptr command_fcb+35, 0
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mov word ptr iogroup:command_fcb+33, 0
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mov word ptr iogroup:command_fcb+35, 0
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; Set record size to 1 byte
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mov word ptr command_fcb+14, 1
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mov word ptr iogroup:command_fcb+14, 1
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; Read command.com into memory
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mov ah, 27h
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@ -326,7 +326,7 @@ chs proc
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; cylinder = LBA / sectorspertrack / heads
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; head = LBA / sectorspertrack % heads
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; sector = LBA % sectorspertrack + 1
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div cs:sectorspertrack
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div iogroup:sectorspertrack
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; ax = LBA / sectorspertrack
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; dx = LBA % sectorspertrack
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@ -335,7 +335,7 @@ chs proc
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inc cl
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xor dx, dx
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div cs:heads
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div iogroup:heads
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; ax = LBA / sectorspertrack / heads
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; dx = LBA / sectorspertrack % heads
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@ -374,15 +374,132 @@ diskchange proc far
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ret
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diskchange endp
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setdate:
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mov al, 'd'
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jmp error
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settime:
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mov al, 't'
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jmp error
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gettime:
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mov al, 'T'
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jmp error
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; IN:
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; ax = days since 1980-01-01
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setdate proc far
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mov iogroup:days_since_epoch, ax
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ret
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setdate endp
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; IN:
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; ch = hour
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; cl = minute
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; dh = second
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; dl = 1/100 second
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settime proc far
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push ax
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push bx
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push cx
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push dx
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push si
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push di
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; Save second & 1/100 second in bx
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mov bx, dx
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; Hour
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mov al, ch
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cbw
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mul iogroup:doubleticks_per_hour
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shl ax, 1
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rcl dx, 1
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; Store the partial sum in si:di
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mov di, ax
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mov si, dx
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; Minute
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mov al, cl
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cbw
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mul iogroup:ticks_per_minute
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add di, ax
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adc si, dx
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; Second
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mov al, bh
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cbw
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mul iogroup:ticks_per_second
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add di, ax
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adc si, dx
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; 1/100 second
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mov al, bl
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cbw
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div iogroup:cs_per_tick
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xor ah, ah
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add di, ax
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adc si, 0
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; Move result to cx:ds and set timer
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mov cx, si
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mov dx, di
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mov ah, 01h
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int 1ah
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pop di
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pop si
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pop dx
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pop cx
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pop bx
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pop ax
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ret
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settime endp
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; OUT:
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; ax = days since 1980-01-01
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; ch = hour
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; cl = minute
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; dh = second
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; dl = 1/100 second
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gettime proc far
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; TODO: Use RTC if available
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push bx
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; Get ticks since midnight and day rollover flag
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xor ah, ah
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int 1ah
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; al is nonzero if day has changed
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test al, al
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jz same_day
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inc iogroup:days_since_epoch
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same_day:
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; Divide the ticks by 2, to keep all our arithmetic within bounds
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shr cx, 1
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rcr dx, 1
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; int 1ah / ah=00 returns the ticks in cx:dx, div operates on dx:ax
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mov ax, dx
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mov dx, cx
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div iogroup:doubleticks_per_hour
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mov ch, al ; Hour
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; Remainder in dx, range [0,doubleticks_per_hour[ represents an hour
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; Multiply by 60, divide by doubleticks_per_hour to get the minute
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mov ax, dx
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mul iogroup:sixty
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div iogroup:doubleticks_per_hour
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mov cl, al ; Minute
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; Do same again to get seconds
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mov ax, dx
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mul iogroup:sixty
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div iogroup:doubleticks_per_hour
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mov bl, al ; Save seconds in bl, since dh gets destroyed by next muldiv
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; For 1/100th of a second, multiply by 100 instead
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mov ax, dx
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mul iogroup:hundred
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div iogroup:doubleticks_per_hour
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mov dh, bl ; Second
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mov dl, al ; 1/100 second
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mov ax, iogroup:days_since_epoch
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pop bx
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ret
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gettime endp
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flush proc far
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push ax
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@ -444,6 +561,14 @@ parameters_320k:
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dw 112 ; Number of directory entries
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dw 320*2 ; Number of sectors
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doubleticks_per_hour dw 32772 ; 1800B0h / 2 / 24
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ticks_per_minute dw 1092 ; 1800B0h / 24 / 60
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ticks_per_second dw 18 ; 1800B0h / 24 / 60 / 60
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cs_per_tick db 5 ; 24 * 60 * 60 * 100 / 1800B0h
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sixty dw 60
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hundred dw 100
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constants ends
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data segment
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@ -453,6 +578,8 @@ command_fcb:
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db "COMMAND COM"
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db 25 dup (?)
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days_since_epoch: dw 0
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data ends
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code segment
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