26a601131d
This reverts commit 9859b44888.
This change causes 2 bugs with the GBC game Cannon Fodder
( Cannon Fodder (U) (M5) [C][!].gbc
md5sum 762d6c94874d8ac894ad100c0a4b50ab )
1) the 3D scenes flicker and there are some artifacts in the title
screen,
2) as soon as mission 2 starts, the CPU goes into an endless loop
and doesn't process input anymore - this is really nasty, as it
is even impossible to get out of gnuboy itself, at least in fb
mode.
i was skeptical about this inofficial patch since the beginning,
since it was not done by laguna himself but by some gamers, and
now it's confirmed that it's broken. afaict this patch includes
3-4 logical changes, if further issues are experienced it may make
sense to try one after the other to see if it fixes them.
182 lines
3 KiB
C
182 lines
3 KiB
C
#include <string.h>
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#include "defs.h"
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#include "cpu.h"
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#include "hw.h"
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#include "regs.h"
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#include "lcd.h"
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#include "mem.h"
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#include "fastmem.h"
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struct hw hw;
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/*
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* hw_interrupt changes the virtual interrupt lines included in the
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* specified mask to the values the corresponding bits in i take, and
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* in doing so, raises the appropriate bit of R_IF for any interrupt
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* lines that transition from low to high.
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*/
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void hw_interrupt(byte i, byte mask)
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{
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byte oldif = R_IF;
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i &= 0x1F & mask;
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R_IF |= i & (hw.ilines ^ i);
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/* FIXME - is this correct? not sure the docs understand... */
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if ((R_IF & (R_IF ^ oldif) & R_IE) && cpu.ime) cpu.halt = 0;
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/* if ((i & (hw.ilines ^ i) & R_IE) && cpu.ime) cpu.halt = 0; */
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/* if ((i & R_IE) && cpu.ime) cpu.halt = 0; */
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hw.ilines &= ~mask;
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hw.ilines |= i;
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}
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/*
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* hw_dma performs plain old memory-to-oam dma, the original dmg
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* dma. Although on the hardware it takes a good deal of time, the cpu
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* continues running during this mode of dma, so no special tricks to
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* stall the cpu are necessary.
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*/
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void hw_dma(byte b)
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{
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int i;
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addr a;
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a = ((addr)b) << 8;
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for (i = 0; i < 160; i++, a++)
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lcd.oam.mem[i] = readb(a);
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}
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void hw_hdma_cmd(byte c)
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{
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int cnt;
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addr sa;
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int da;
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/* Begin or cancel HDMA */
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if ((hw.hdma|c) & 0x80)
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{
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hw.hdma = c;
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R_HDMA5 = c & 0x7f;
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return;
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}
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/* Perform GDMA */
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sa = ((addr)R_HDMA1 << 8) | (R_HDMA2&0xf0);
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da = 0x8000 | ((int)(R_HDMA3&0x1f) << 8) | (R_HDMA4&0xf0);
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cnt = ((int)c)+1;
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/* FIXME - this should use cpu time! */
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/*cpu_timers(102 * cnt);*/
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cnt <<= 4;
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while (cnt--)
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writeb(da++, readb(sa++));
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R_HDMA1 = sa >> 8;
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R_HDMA2 = sa & 0xF0;
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R_HDMA3 = 0x1F & (da >> 8);
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R_HDMA4 = da & 0xF0;
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R_HDMA5 = 0xFF;
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}
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void hw_hdma()
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{
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int cnt;
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addr sa;
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int da;
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sa = ((addr)R_HDMA1 << 8) | (R_HDMA2&0xf0);
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da = 0x8000 | ((int)(R_HDMA3&0x1f) << 8) | (R_HDMA4&0xf0);
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cnt = 16;
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while (cnt--)
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writeb(da++, readb(sa++));
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R_HDMA1 = sa >> 8;
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R_HDMA2 = sa & 0xF0;
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R_HDMA3 = 0x1F & (da >> 8);
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R_HDMA4 = da & 0xF0;
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R_HDMA5--;
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hw.hdma--;
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}
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/*
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* pad_refresh updates the P1 register from the pad states, generating
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* the appropriate interrupts (by quickly raising and lowering the
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* interrupt line) if a transition has been made.
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*/
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void pad_refresh()
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{
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byte oldp1;
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oldp1 = R_P1;
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R_P1 &= 0x30;
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R_P1 |= 0xc0;
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if (!(R_P1 & 0x10))
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R_P1 |= (hw.pad & 0x0F);
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if (!(R_P1 & 0x20))
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R_P1 |= (hw.pad >> 4);
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R_P1 ^= 0x0F;
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if (oldp1 & ~R_P1 & 0x0F)
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{
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hw_interrupt(IF_PAD, IF_PAD);
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hw_interrupt(0, IF_PAD);
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}
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}
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/*
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* These simple functions just update the state of a button on the
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* pad.
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*/
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void pad_press(byte k)
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{
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if (hw.pad & k)
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return;
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hw.pad |= k;
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pad_refresh();
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}
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void pad_release(byte k)
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{
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if (!(hw.pad & k))
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return;
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hw.pad &= ~k;
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pad_refresh();
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}
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void pad_set(byte k, int st)
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{
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st ? pad_press(k) : pad_release(k);
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}
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void hw_reset()
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{
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hw.ilines = hw.pad = 0;
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memset(ram.hi, 0, sizeof ram.hi);
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R_P1 = 0xFF;
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R_LCDC = 0x91;
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R_BGP = 0xFC;
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R_OBP0 = 0xFF;
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R_OBP1 = 0xFF;
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R_SVBK = 0x01;
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R_HDMA5 = 0xFF;
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R_VBK = 0xFE;
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}
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