;
; SNTP library
;
; (C) 2019 Coldy
; Thank's you for use this code and software based on it!
; I will glad if it's will be helpful.
;
; Distributed under terms of GPL
;
; Inline clearing register(s)
; E.g. uses:
; clear eax ; - clearing single register
; or
; clear eax, ebx ; ... and so on - clearing multiple register
macro clear [reg] { xor reg, reg }
macro b2bcd
; Convert hex byte to BCD byte
; Input:
; al = number 0...99 (not checking)
; Output:
; al = number in BCD
; Algorithm:
; al = (al > 9) ? ((al / 10) * 6 + al) : al
; Use registers (not restore):
; eax, ebx, edx
{
clear ebx, edx
cmp al, 9 ; (al <= 9 ?)
jle @f
mov bl, al
mov dl, 10
div dl ; al = al/10
mov dl, 6
mul dl ; al = al*6
add al, bl ; al = al + bl
@@:
}
struct DateTime
struct
day db ?
month db ?
year dw ?
ends
struct
hour db ?
min db ?
sec db ?
ends
ends
proc DateTime2bcd
;
; Input:
; eax => pointer to DateTime (UNIX time since 1.1.1970 00:00:00 GMT )
;
; Output:
; eax => time in ÂÑD format
; edx => date in BCD format
locals
date dd 0
time dd 0
endl
mov esi, eax
clear eax, ebx, ecx
mov al, [esi + DateTime.day]
cmp al, 9
jle @f
mov bl, al
mov cl, 10
div cl
mul bl, cl
add al, bl
@@:
endp
YEAR_EPOCH = 1970
YEAR_FIRST_LEAP_YEAR = 1972
SEC_IN_MINUTE = 60
SEC_IN_HOUR = (SEC_IN_MINUTE * 60)
SEC_IN_DAY = (SEC_IN_HOUR * 24)
SEC_IN_YEAR = (SEC_IN_DAY * 365)
proc timestamp2DateTime
;
; Input:
; eax => timestamp (UNIX time since 1.1.1970 00:00:00 GMT )
; ebx => pointer to DateTime
;
; Output:
; none
;
; Use registers (not restore):
;
; History:
; 14.04.2019 Bug fixed: Incorrect output day (-1 day error)!!!
; 19.04.2019 Bug fixed: Incorrect convert of time with maximum UNIX time (0x7ffffff)
;
; Known isuues:
; Not yet seen :)
;
locals
timestamp dd ?
years dw ?
lyears dw ?
;year dw ?
;_ts dd 0
;ts dd 0
MonthDays db 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
;month db ?
endl
;pusha
mov [timestamp], eax
mov esi, ebx ; ESI => pointer to DateTime
; Calculate total years since year epoch
cdq
mov ebx, SEC_IN_YEAR + SEC_IN_DAY/4
idiv ebx
mov [years], ax ; (AX => years)
; Calculate current year
add ax, YEAR_EPOCH
mov [esi + DateTime.year], ax ; (AX => year)
; Calculate leap years since year epoch
;xor ecx, ecx ; Clear
;mov cx, bx
;Fix: -1 day error
dec ax
sub ax, YEAR_FIRST_LEAP_YEAR ; - 1
clear ebx, edx
mov bx, 4
idiv bx
cmp [esi + DateTime.year], YEAR_FIRST_LEAP_YEAR + 1
js @f
inc al
@@:
mov [lyears], ax
; Drop years seconds
mov eax, [timestamp]
clear ebx
mov bx, [years]
sub bx, [lyears]
mov ecx, SEC_IN_YEAR
imul ebx, ecx ; ebx => (years - lyears) * SEC_IN_YEAR
clear ecx
mov cx, [lyears]
mov edx, SEC_IN_YEAR + SEC_IN_DAY
imul ecx, edx ; cx => lyears * (SEC_IN_YEAR + SEC_IN_DAY)
add ebx, ecx ; bx => (years - lyears) * SEC_IN_YEAR + lyears * (SEC_IN_YEAR + SEC_IN_DAY)
sub eax, ebx
mov [timestamp], eax
;Is leap year?
clear ecx, edx
mov cx, [esi + DateTime.year]
mov eax, ecx
mov ebx, 4
div bx
cmp dx, 0
je leap
mov ax, cx
mov bx, 100
div bx
cmp dx, 0
je leap
mov ax, cx
mov bx, 400
clear dx
div bx
cmp dx, 0
jmp @f
leap:
; Add +1 day in february if leap year
inc [MonthDays + 1]
@@:
; Calculate current month
clear eax, ecx, edi ; _ts, ts, month (Bug? => ecx != 0)
caclmonth:
clear ebx
mov bl, [MonthDays + edi]
imul ebx, SEC_IN_DAY
inc edi
add eax, ebx
; {{ 19.4.2019 Bug was somewhere here
cmp edi, 12
je @f
; TODO: if edi >= 12 then error!
;mov eax, -1
;mov edx, 0
;ret
;@@:
cmp eax, [timestamp]
jge @f ; Bug? => jg @f
mov ecx, eax
jmp caclmonth
; }}
@@:
; Drop months seconds
sub [timestamp], ecx
mov eax, edi
mov [esi + DateTime.month], al
; Calculate elapsed day
mov eax, [timestamp]
clear edx
mov ebx, SEC_IN_DAY
idiv ebx ; eax => day
; Drop days seconds
imul ebx, eax, SEC_IN_DAY
sub [timestamp],ebx
; Correct current day
add eax, 1 ; eax => current day
mov [esi + DateTime.day], al
; Calculate current hour
mov eax, [timestamp]
clear edx
mov ebx, SEC_IN_HOUR
idiv ebx
mov [esi + DateTime.hour], al
; Drop hours seconds
imul ebx, eax, SEC_IN_HOUR
sub [timestamp],ebx
mov eax, [timestamp]
clear edx
mov ebx, SEC_IN_MINUTE
idiv ebx
mov [esi + DateTime.min], al
; Drop minutes seconds
imul ebx, eax, SEC_IN_MINUTE
sub [timestamp],ebx
mov eax, [timestamp]
mov [esi + DateTime.sec], al
;popa
ret
endp