hw.c

来自「日本的手持pda源码.wince下使用,完全开源」· C语言 代码 · 共 202 行

#include "defs.h"
#include "cpu.h"
#include "hw.h"
#include "regs.h"
#include "lcd.h"
#include "mem.h"
#include "fastmem.h"


struct hw hw;

extern int dma[3];

/*
 * hw_interrupt changes the virtual interrupt lines included in the
 * specified mask to the values the corresponding bits in i take, and
 * in doing so, raises the appropriate bit of R_IF for any interrupt
 * lines that transition from low to high.
 */

void hw_interrupt(byte i)
{
	if (!(R_LCDC & 0x80) && (i & (IF_VBLANK | IF_STAT)))
		return;

	R_IF |= i;
	if (R_IF & R_IE) cpu.halt = 0;
}


/*
 * hw_dma performs plain old memory-to-oam dma, the original dmg
 * dma. Although on the hardware it takes a good deal of time, the cpu
 * continues running during this mode of dma, so no special tricks to
 * stall the cpu are necessary.
 */

INLINE hw_dma_copy(int da, int sa, int cnt)
{
	byte *src = mbc.rmap[sa>>12];
	if (src) {
#if 1
		switch (da >> 12) {
		case 8:
		case 9:
			vram_copy(da & 0x1fff, src + sa, cnt);
			break;
		default:
			while (cnt--)
				writeb(da++, src[sa++]);
		}
#else
		while (cnt--)
			writeb(da++, src[sa++]);
#endif
	}
	else {
		while (cnt--)
			writeb(da++, readb(sa++));
	}
}

void hw_dma(byte b)
{
	int i;
	int a;
	byte* ps;

	a = ((int)b) << 8;
	ps = mbc.rmap[a>>12];
	if (ps)
		memcpy(&lcd.oam.mem[0], &ps[a], 160);
	else {
		for (i = 0; i < 160; i++)
			lcd.oam.mem[i] = readb(a + i);
	}
}

void hw_hdma_cmd(byte c)
{
	int cnt;
	int sa, da;

	/* Begin or cancel HDMA */
	if ((hw.hdma|c) & 0x80)
	{
		hw.hdma = c;
		R_HDMA5 = c & 0x7f;
		return;
	}
	
	/* Perform GDMA */
	sa = ((int)R_HDMA1 << 8) | (R_HDMA2&0xf0);
	da = 0x8000 | ((int)(R_HDMA3&0x1f) << 8) | (R_HDMA4&0xf0);
	cnt = ((int)c)+1;
	/* FIXME - this should use cpu time! */
	/*cpu_timers(102 * cnt);*/
	cnt <<= 4;

	hw_dma_copy(da, sa, cnt);
	sa += cnt;
	da += cnt;

	R_HDMA1 = sa >> 8;
	R_HDMA2 = sa & 0xF0;
	R_HDMA3 = 0x1F & (da >> 8);
	R_HDMA4 = da & 0xF0;
	R_HDMA5 = 0xFF;
}


void hw_hdma()
{
	int cnt;
	int sa, da;

	sa = ((int)R_HDMA1 << 8) | (R_HDMA2&0xf0);
	da = 0x8000 | ((int)(R_HDMA3&0x1f) << 8) | (R_HDMA4&0xf0);
	cnt = 16;

	hw_dma_copy(da, sa, cnt);
	sa += cnt;
	da += cnt;

	R_HDMA1 = sa >> 8;
	R_HDMA2 = sa & 0xF0;
	R_HDMA3 = 0x1F & (da >> 8);
	R_HDMA4 = da & 0xF0;
	R_HDMA5--;
	hw.hdma--;
}


/*
 * pad_refresh updates the P1 register from the pad states, generating
 * the appropriate interrupts (by quickly raising and lowering the
 * interrupt line) if a transition has been made.
 */

void pad_refresh()
{
	byte oldp1;
	oldp1 = R_P1;
	R_P1 &= 0x30;
	R_P1 |= 0xc0;
	if (!(R_P1 & 0x10))
		R_P1 |= (hw.pad & 0x0F);
	if (!(R_P1 & 0x20))
		R_P1 |= (hw.pad >> 4);
	R_P1 ^= 0x0F;
	if (oldp1 & ~R_P1 & 0x0F)
		hw_interrupt(IF_PAD);
}


/*
 * These simple functions just update the state of a button on the
 * pad.
 */

void pad_press(byte k)
{
	if (hw.pad & k)
		return;
	hw.pad |= k;
	pad_refresh();
}

void pad_release(byte k)
{
	if (!(hw.pad & k))
		return;
	hw.pad &= ~k;
	pad_refresh();
}

void pad_set(byte k, int st)
{
	st ? pad_press(k) : pad_release(k);
}

void hw_reset()
{
	hw.pad = 0;
	hw.vblank = 0;

	memset(ram.hi, 0, sizeof ram.hi);

	R_P1 = 0xFF;
	R_LCDC = 0x91;
	R_BGP = 0xFC;
	R_OBP0 = 0xFF;
	R_OBP1 = 0xFF;
	R_SVBK = 0x01;
	R_HDMA5 = 0xFF;
	R_VBK = 0xFE;
}