adler32.inc

The dinamyc link library that contains an implementation of SHA1, SHA512, CRC32, CRC32b, Adler32, Tw

; ----------------------------------------------------- ;
;    Adler32 checksum algorithm                         ;
; ----------------------------------------------------- ;

align 4
proc Adler32_Init,Adler32:PDWORD
     mov eax,[Adler32]
     mov dword [eax],1
     ret
endp

align 4
proc Adler32_Update uses ebx esi,Buffer:PBYTE,BufSize:DWORD,Adler32:PDWORD
     mov esi,[Buffer]
     mov ecx,[BufSize]
     mov ebx,[Adler32]
     mov ebx,[ebx]
     mov edx,ebx
     shr edx,16
     shl ebx,16
     shr ebx,16
     xor eax,eax
     jecxz .a32_end
.a32_loop:
     mov al,[esi]
     add ebx,eax
     cmp ebx,$FFF1
     jb @f
     sub ebx,$FFF1
@@:  add edx,ebx
     cmp edx,$FFF1
     jb @f
     sub edx,$FFF1
@@:  inc esi
     loop .a32_loop
.a32_end:
     shl edx,16
     add edx,ebx
     mov eax,[Adler32]
     mov [eax],edx
     ret
endp