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 1056... Line 1056...
1056 
; One transfer descriptor can describe up to two pages.
 1056 
; One transfer descriptor can describe up to two pages.
1057 
; In the worst case (when the buffer is something*1000h+0FFFh)
 1057 
; In the worst case (when the buffer is something*1000h+0FFFh)
1058 
; this corresponds to 1001h bytes. If the requested size is
 1058 
; this corresponds to 1001h bytes. If the requested size is
1059 
; greater, we should split the transfer into several descriptors.
 1059 
; greater, we should split the transfer into several descriptors.
1060 
; Boundaries to split must be multiples of endpoint transfer size
 1060 
; Boundaries to split must be multiples of endpoint transfer size
1061 
; to avoid short packets except in the end of the transfer,
 1061 
; to avoid short packets except in the end of the transfer.
- 
 
 1062 
        cmp     [size], 1001h
1062 
; 1000h is always a good value.
 1063 
        jbe     .lastpacket
1063 
; 2. While the remaining data cannot fit in one packet,
 1064 
; 2. While the remaining data cannot fit in one packet,
1064 
; allocate page-sized descriptors.
 1065 
; allocate full-sized descriptors.
- 
 
 1066 
; 2a. Calculate size of one descriptor: must be a multiple of transfer size
- 
 
 1067 
; and must be not greater than 1001h.
- 
 
 1068 
        movzx   ecx, word [ebx+ohci_pipe.Flags+2-sizeof.ohci_pipe]
1065 
        mov     edi, 1000h
 1069 
        mov     eax, 1001h
- 
 
 1070 
        xor     edx, edx
- 
 
 1071 
        mov     edi, eax
- 
 
 1072 
        div     ecx
- 
 
 1073 
        sub     edi, edx
- 
 
 1074 
; 2b. Allocate in loop.
1066 
        mov     [packetSize], edi
 1075 
        mov     [packetSize], edi
1067 
.fullpackets:
 1076 
.fullpackets:
1068 
        cmp     [size], edi
 - 
 
1069 
        jbe     .lastpacket
 - 
 
1070 
        call    ohci_alloc_packet
 1077 
        call    ohci_alloc_packet
1071 
        test    eax, eax
 1078 
        test    eax, eax
1072 
        jz      .fail
 1079 
        jz      .fail
1073 
        mov     [td], eax
 1080 
        mov     [td], eax
1074 
        add     [buffer], edi
 1081 
        add     [buffer], edi
1075 
        sub     [size], edi
 1082 
        sub     [size], edi
- 
 
 1083 
        cmp     [size], 1001h
1076 
        jmp     .fullpackets
 1084 
        ja      .fullpackets
1077 
; 3. The remaining data can fit in one descriptor;
 1085 
; 3. The remaining data can fit in one descriptor;
1078 
; allocate the last descriptor with size = size of remaining data.
 1086 
; allocate the last descriptor with size = size of remaining data.
1079 
.lastpacket:
 1087 
.lastpacket:
1080 
        mov     eax, [size]
 1088 
        mov     eax, [size]
1081 
        mov     [packetSize], eax
 1089 
        mov     [packetSize], eax