apps/plugins/rockboy/hw.c

   1
   2
   3
   4 #include "rockmacros.h"
   5 #include "defs.h"
   6 #include "cpu-gb.h"
   7 #include "hw.h"
   8 #include "regs.h"
   9 #include "lcd-gb.h"
  10 #include "mem.h"
  11 #include "fastmem.h"
  12
  13
  14 struct hw hw IBSS_ATTR;
  15
  16
  17
  18 /*
  19  * hw_interrupt changes the virtual interrupt lines included in the
  20  * specified mask to the values the corresponding bits in i take, and
  21  * in doing so, raises the appropriate bit of R_IF for any interrupt
  22  * lines that transition from low to high.
  23  */
  24
  25 void hw_interrupt(byte i, byte mask)
  26 {
  27     byte oldif = R_IF;
  28     i &= 0x1F & mask;
  29     R_IF |= i & (hw.ilines ^ i);
  30
  31     /* FIXME - is this correct? not sure the docs understand... */
  32     if ((R_IF & (R_IF ^ oldif) & R_IE) && cpu.ime) cpu.halt = 0;
  33     /* if ((i & (hw.ilines ^ i) & R_IE) && cpu.ime) cpu.halt = 0; */
  34     /* if ((i & R_IE) && cpu.ime) cpu.halt = 0; */
  35
  36     hw.ilines &= ~mask;
  37     hw.ilines |= i;
  38 }
  39
  40
  41 /*
  42  * hw_dma performs plain old memory-to-oam dma, the original dmg
  43  * dma. Although on the hardware it takes a good deal of time, the cpu
  44  * continues running during this mode of dma, so no special tricks to
  45  * stall the cpu are necessary.
  46  */
  47
  48 void hw_dma(byte b)
  49 {
  50     int i;
  51     addr a;
  52
  53     a = ((addr)b) << 8;
  54     for (i = 0; i < 160; i++, a++)
  55         lcd.oam.mem[i] = readb(a);
  56 }
  57
  58 void hw_hdma(void)
  59 {
  60     int cnt;
  61     addr sa;
  62     int da;
  63
  64     sa = ((addr)R_HDMA1 << 8) | (R_HDMA2&0xf0);
  65     da = 0x8000 | ((int)(R_HDMA3&0x1f) << 8) | (R_HDMA4&0xf0);
  66     for (cnt=16; cnt>0; cnt--)
  67         writeb(da++, readb(sa++));
  68     cpu_timers(16);
  69     R_HDMA1 = sa >> 8;
  70     R_HDMA2 = sa & 0xF0;
  71     R_HDMA3 = 0x1F & (da >> 8);
  72     R_HDMA4 = da & 0xF0;
  73     R_HDMA5--;
  74     hw.hdma--;
  75 }
  76
  77 void hw_hdma_cmd(byte c)
  78 {
  79     int cnt;
  80     addr sa;
  81     int da;
  82
  83     /* Begin or cancel HDMA */
  84     if ((hw.hdma|c) & 0x80)
  85     {
  86         hw.hdma = c;
  87         R_HDMA5 = c & 0x7f;
  88         if ((R_STAT&0x03) == 0x00) hw_hdma();
  89         return;
  90     }
  91
  92     /* Perform GDMA */
  93     sa = ((addr)R_HDMA1 << 8) | (R_HDMA2&0xf0);
  94     da = 0x8000 | ((int)(R_HDMA3&0x1f) << 8) | (R_HDMA4&0xf0);
  95     cnt = (((int)c)+1) << 4;
  96     /* FIXME - this should use cpu time! */
  97     /*cpu_timers(102 * cnt);*/
  98     cpu_timers((460>>cpu.speed)+cnt); /*dalias*/
  99         /*cpu_timers(228 + (16*cnt));*/ /* this should be right according to no$ */
 100     while (cnt--)
 101         writeb(da++, readb(sa++));
 102     R_HDMA1 = sa >> 8;
 103     R_HDMA2 = sa & 0xF0;
 104     R_HDMA3 = 0x1F & (da >> 8);
 105     R_HDMA4 = da & 0xF0;
 106     R_HDMA5 = 0xFF;
 107 }
 108
 109
 110 /*
 111  * pad_refresh updates the P1 register from the pad states, generating
 112  * the appropriate interrupts (by quickly raising and lowering the
 113  * interrupt line) if a transition has been made.
 114  */
 115
 116 void pad_refresh(void)
 117 {
 118     byte oldp1;
 119     oldp1 = R_P1;
 120     R_P1 &= 0x30;
 121     R_P1 |= 0xc0;
 122     if (!(R_P1 & 0x10))
 123         R_P1 |= (hw.pad & 0x0F);
 124     if (!(R_P1 & 0x20))
 125         R_P1 |= (hw.pad >> 4);
 126     R_P1 ^= 0x0F;
 127     if (oldp1 & ~R_P1 & 0x0F)
 128     {
 129         hw_interrupt(IF_PAD, IF_PAD);
 130         hw_interrupt(0, IF_PAD);
 131     }
 132 }
 133
 134
 135 /*
 136  * These simple functions just update the state of a button on the
 137  * pad.
 138  */
 139
 140 static void pad_press(byte k) ICODE_ATTR;
 141 static void pad_press(byte k)
 142 {
 143     if (hw.pad & k)
 144         return;
 145     hw.pad |= k;
 146     pad_refresh();
 147 }
 148
 149 static void pad_release(byte k) ICODE_ATTR;
 150 static void pad_release(byte k)
 151 {
 152     if (!(hw.pad & k))
 153         return;
 154     hw.pad &= ~k;
 155     pad_refresh();
 156 }
 157
 158 void pad_set(byte k, int st)
 159 {
 160     st ? pad_press(k) : pad_release(k);
 161 }
 162
 163 void hw_reset(void)
 164 {
 165     hw.ilines = hw.pad = 0;
 166
 167     memset(ram.hi, 0, sizeof ram.hi);
 168
 169     R_P1 = 0xFF;
 170     R_LCDC = 0x91;
 171     R_BGP = 0xFC;
 172     R_OBP0 = 0xFF;
 173     R_OBP1 = 0xFF;
 174     R_SVBK = 0x01;
 175     R_HDMA5 = 0xFF;
 176     R_VBK = 0xFE;
 177 }