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Annotation of uae/src/dos-dma.c, revision 1.1.1.1

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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