Subversion Repositories Kolibri OS

Rev

Rev 3653 | Go to most recent revision | Show entire file | Regard whitespace | Details | Blame | Last modification | View Log | RSS feed

Rev 3653 Rev 3656
Line 1043... Line 1043...
1043 
; One transfer descriptor can describe up to 5 pages.
 1043 
; One transfer descriptor can describe up to 5 pages.
1044 
; In the worst case (when the buffer is something*1000h+0FFFh)
 1044 
; In the worst case (when the buffer is something*1000h+0FFFh)
1045 
; this corresponds to 4001h bytes. If the requested size is
 1045 
; this corresponds to 4001h bytes. If the requested size is
1046 
; greater, we should split the transfer into several descriptors.
 1046 
; greater, we should split the transfer into several descriptors.
1047 
; Boundaries to split must be multiples of endpoint transfer size
 1047 
; Boundaries to split must be multiples of endpoint transfer size
1048 
; to avoid short packets except in the end of the transfer,
 1048 
; to avoid short packets except in the end of the transfer.
- 
 
 1049 
        cmp     [size], 4001h
1049 
; 4000h is always a good value.
 1050 
        jbe     .lastpacket
1050 
; 2. While the remaining data cannot fit in one descriptor,
 1051 
; 2. While the remaining data cannot fit in one descriptor,
1051 
; allocate full descriptors (of maximal possible size).
 1052 
; allocate full descriptors (of maximal possible size).
- 
 
 1053 
; 2a. Calculate size of one descriptor: must be a multiple of transfer size
- 
 
 1054 
; and must be not greater than 4001h.
- 
 
 1055 
        movzx   ecx, word [ebx+ohci_pipe.Flags+2-sizeof.ohci_pipe]
1052 
        mov     edi, 4000h
 1056 
        mov     eax, 4001h
- 
 
 1057 
        xor     edx, edx
- 
 
 1058 
        mov     edi, eax
- 
 
 1059 
        div     ecx
- 
 
 1060 
        sub     edi, edx
1053 
        mov     [packetSize], edi
 1061 
        mov     [packetSize], edi
1054 
.fullpackets:
 1062 
.fullpackets:
1055 
        cmp     [size], edi
 - 
 
1056 
        jbe     .lastpacket
 - 
 
1057 
        call    ehci_alloc_packet
 1063 
        call    ehci_alloc_packet
1058 
        test    eax, eax
 1064 
        test    eax, eax
1059 
        jz      .fail
 1065 
        jz      .fail
1060 
        mov     [td], eax
 1066 
        mov     [td], eax
1061 
        add     [buffer], edi
 1067 
        add     [buffer], edi
1062 
        sub     [size], edi
 1068 
        sub     [size], edi
- 
 
 1069 
        cmp     [size], 4001h
1063 
        jmp     .fullpackets
 1070 
        ja      .fullpackets
1064 
; 3. The remaining data can fit in one packet;
 1071 
; 3. The remaining data can fit in one packet;
1065 
; allocate the last descriptor with size = size of remaining data.
 1072 
; allocate the last descriptor with size = size of remaining data.
1066 
.lastpacket:
 1073 
.lastpacket:
1067 
        mov     eax, [size]
 1074 
        mov     eax, [size]
1068 
        mov     [packetSize], eax
 1075 
        mov     [packetSize], eax