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Annotation of uae/src/dos-dma.c, revision 1.1

1.1     ! root        1:  /*
        !             2:   * UAE - The Un*x Amiga Emulator
        !             3:   *
        !             4:   * DOS DMA interface.
        !             5:   *
        !             6:   * (c) 1996 Peter Remmers
        !             7:   */
        !             8: 
        !             9: #include <stdlib.h>
        !            10: #include <pc.h>
        !            11: #include <dpmi.h>
        !            12: 
        !            13: #include "dos-dma.h"
        !            14: 
        !            15: /* some useful macros */
        !            16: #define LOBYTE(x) ((unsigned char)(((unsigned short)(x)) &  0xFF))
        !            17: #define HIBYTE(x) ((unsigned char)(((unsigned short)(x)) >> 8))
        !            18: #define LOWORD(x) ((unsigned short)(((unsigned long)(x)) & 0xFFFF))
        !            19: #define HIWORD(x) ((unsigned short)(((unsigned long)(x)) >> 16))
        !            20: 
        !            21: const unsigned short DMA_Address [8] = {0x00,0x02,0x04,0x06,0xC0,0xC4,0xC8,0xCC};
        !            22: const unsigned short DMA_Count   [8] = {0x01,0x03,0x05,0x07,0xC2,0xC6,0xCA,0xCE};
        !            23: 
        !            24: const unsigned short DMA_PageLo[8]= { 0x87, 0x83, 0x81, 0x82, 0x8F, 0x8B, 0x89, 0x8A};
        !            25: const unsigned short DMA_PageHi[8]= {0x487,0x483,0x481,0x482,0x48F,0x48B,0x489,0x48A};
        !            26: 
        !            27: #define DMA_Status(ch)        ((ch)<4 ? 0x08 : 0xD0)  /* Read  */
        !            28: #define DMA_Command(ch)       ((ch)<4 ? 0x08 : 0xD0)  /* Write */
        !            29: #define DMA_Request(ch)       ((ch)<4 ? 0x09 : 0xD2)
        !            30: #define DMA_MaskSingle(ch)    ((ch)<4 ? 0x0A : 0xD4)
        !            31: #define DMA_Mode(ch)          ((ch)<4 ? 0x0B : 0xD6)
        !            32: #define DMA_ClearFF(ch)       ((ch)<4 ? 0x0C : 0xD8)
        !            33: #define DMA_Latch(ch)         ((ch)<4 ? 0x0D : 0xDA)  /* Read  */
        !            34: #define DMA_MasterClear(ch)   ((ch)<4 ? 0x0D : 0xDA)  /* Write */
        !            35: #define DMA_ClearMask(ch)     ((ch)<4 ? 0x0E : 0xDC)
        !            36: #define DMA_MaskAll(ch)       ((ch)<4 ? 0x0F : 0xDE)
        !            37: 
        !            38: 
        !            39: /* allocate DOS memory that does not cross a physical 64k boundary */
        !            40: unsigned long DMA_AllocDMABuf  (_go32_dpmi_seginfo *info)
        !            41: {
        !            42:   unsigned long Phys;
        !            43:   unsigned long bytes;
        !            44: 
        !            45:   /* first allocate requested size */
        !            46:   if (_go32_dpmi_allocate_dos_memory (info)) return (NULL);
        !            47: 
        !            48:   Phys  = (info->rm_segment) << 4;
        !            49:   bytes = (info->size)       << 4;
        !            50:   
        !            51:   /* if memory does not cross boundary we are lucky and that's it */
        !            52:   if (HIWORD(Phys + bytes) == HIWORD (Phys)) return (Phys);
        !            53: 
        !            54:   /* if not, free memory */
        !            55:   _go32_dpmi_free_dos_memory (info);
        !            56: 
        !            57:   /* and allocate twice the requested size */
        !            58:   bytes      <<= 1;
        !            59:   info->size <<= 1;
        !            60:   if (_go32_dpmi_allocate_dos_memory (info)) return (NULL);
        !            61: 
        !            62:   /* and take the half that does not cross a boundary */
        !            63:   Phys = (info->rm_segment) << 4;
        !            64:   if (HIWORD(Phys + bytes) == HIWORD (Phys)) return (Phys);
        !            65:   
        !            66:   return (Phys + (bytes>>1));
        !            67: }
        !            68: 
        !            69: void DMA_Mask (unsigned char channel)
        !            70: {
        !            71:   outportb(DMA_MaskSingle(channel), 4 + (channel&3));
        !            72: }
        !            73: 
        !            74: void DMA_UnMask (unsigned char channel)
        !            75: {
        !            76:   outportb(DMA_MaskSingle(channel), channel&3);
        !            77: }
        !            78: 
        !            79: void DMA_InitTransfer (unsigned char channel, unsigned char Mode,
        !            80:                        unsigned long PhysAddr, unsigned short Count)
        !            81: {
        !            82:   unsigned short Page;
        !            83:   unsigned short Addr;
        !            84: 
        !            85:   if (channel & 4) Count >>= 1;
        !            86:   Count--;
        !            87:   
        !            88:   Page = HIWORD(PhysAddr);
        !            89:   if (channel & 4) PhysAddr >>= 1;
        !            90:   Addr = LOWORD (PhysAddr);
        !            91: 
        !            92:   outportb (DMA_MaskSingle(channel), (channel&3) + 0x04);
        !            93:   outportb (DMA_Mode      (channel), (channel&3) | (Mode&0xFC));
        !            94:   outportb (DMA_ClearFF   (channel), 0);
        !            95:   outportb (DMA_Count     [channel], LOBYTE(Count));
        !            96:   outportb (DMA_Count     [channel], HIBYTE(Count));
        !            97:   outportb (DMA_Address   [channel], LOBYTE(Addr));
        !            98:   outportb (DMA_Address   [channel], HIBYTE(Addr));
        !            99:   outportb (DMA_PageLo    [channel], LOBYTE(Page));
        !           100:   outportb (DMA_PageHi    [channel], HIBYTE(Page));
        !           101:   outportb (DMA_MaskSingle(channel), channel&3);
        !           102: }

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