fastmem.h

   1
   2 #ifndef __FASTMEM_H__
   3 #define __FASTMEM_H__
   4
   5
   6 #include "defs.h"
   7 #include "mem.h"
   8
   9
  10 static byte readb(int a)
  11 {
  12         byte *p = mbc.rmap[a>>12];
  13         if (p) return p[a];
  14         else return mem_read(a);
  15 }
  16
  17 static void writeb(int a, byte b)
  18 {
  19         byte *p = mbc.wmap[a>>12];
  20         if (p) p[a] = b;
  21         else mem_write(a, b);
  22 }
  23
  24 static int readw(int a)
  25 {
  26         if ((a+1) & 0xfff)
  27         {
  28                 byte *p = mbc.rmap[a>>12];
  29                 if (p)
  30                 {
  31 #ifdef IS_LITTLE_ENDIAN
  32 #ifndef ALLOW_UNALIGNED_IO
  33                         if (a&1) return p[a] | (p[a+1]<<8);
  34 #endif
  35                         return *(word *)(p+a);
  36 #else
  37                         return p[a] | (p[a+1]<<8);
  38 #endif
  39                 }
  40         }
  41         return mem_read(a) | (mem_read(a+1)<<8);
  42 }
  43
  44 static void writew(int a, int w)
  45 {
  46         if ((a+1) & 0xfff)
  47         {
  48                 byte *p = mbc.wmap[a>>12];
  49                 if (p)
  50                 {
  51 #ifdef IS_LITTLE_ENDIAN
  52 #ifndef ALLOW_UNALIGNED_IO
  53                         if (a&1)
  54                         {
  55                                 p[a] = w;
  56                                 p[a+1] = w >> 8;
  57                                 return;
  58                         }
  59 #endif
  60                         *(word *)(p+a) = w;
  61                         return;
  62 #else
  63                         p[a] = w;
  64                         p[a+1] = w >> 8;
  65                         return;
  66 #endif
  67                 }
  68         }
  69         mem_write(a, w);
  70         mem_write(a+1, w>>8);
  71 }
  72
  73 static byte readhi(int a)
  74 {
  75         return readb(a | 0xff00);
  76 }
  77
  78 static void writehi(int a, byte b)
  79 {
  80         writeb(a | 0xff00, b);
  81 }
  82
  83 #if 0
  84 static byte readhi(int a)
  85 {
  86         byte (*rd)() = hi_read[a];
  87         return rd ? rd(a) : (ram.hi[a] | himask[a]);
  88 }
  89
  90 static void writehi(int a, byte b)
  91 {
  92         byte (*wr)() = hi_write[a];
  93         if (wr) wr(a, b);
  94         else ram.hi[a] = b & ~himask[a];
  95 }
  96 #endif
  97
  98
  99 #endif