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EGA: Backported the SVGA remapping parts to EGA as it actually works better in some cases, e.g.: FantasyLand on EGA.

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This commit is contained in:
TC1995
2022-06-12 20:03:34 +02:00
parent 9771cd5903
commit dbea8ec715
4 changed files with 309 additions and 236 deletions
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111
src/include/86box/vid_ega_render_remap.h Normal file
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@@ -0,0 +1,111 @@
#ifndef VIDEO_EGA_RENDER_REMAP_H
# define VIDEO_EGA_RENDER_REMAP_H
#define VAR_BYTE_MODE (0 << 0)
#define VAR_WORD_MODE_MA13 (1 << 0)
#define VAR_WORD_MODE_MA15 (2 << 0)
#define VAR_DWORD_MODE (3 << 0)
#define VAR_MODE_MASK (3 << 0)
#define VAR_ROW0_MA13 (1 << 2)
#define VAR_ROW1_MA14 (1 << 3)
#define ADDRESS_REMAP_FUNC(nr) \
static uint32_t address_remap_func_ ## nr(ega_t *ega, uint32_t in_addr) \
{ \
uint32_t out_addr; \
\
switch (nr & VAR_MODE_MASK) \
{ \
case VAR_BYTE_MODE: \
out_addr = in_addr; \
break; \
\
case VAR_WORD_MODE_MA13: \
out_addr = ((in_addr << 1) & 0x1fff8) | \
((in_addr >> 13) & 0x4) | \
(in_addr & ~0x1ffff); \
break; \
\
case VAR_WORD_MODE_MA15: \
out_addr = ((in_addr << 1) & 0x1fff8) | \
((in_addr >> 15) & 0x4) | \
(in_addr & ~0x1ffff); \
break; \
\
case VAR_DWORD_MODE: \
out_addr = ((in_addr << 2) & 0x3fff0) | \
((in_addr >> 14) & 0xc) | \
(in_addr & ~0x3ffff); \
break; \
} \
\
if (nr & VAR_ROW0_MA13) \
out_addr = (out_addr & ~0x8000) | \
((ega->sc & 1) ? 0x8000 : 0); \
if (nr & VAR_ROW1_MA14) \
out_addr = (out_addr & ~0x10000) | \
((ega->sc & 2) ? 0x10000 : 0); \
\
return out_addr; \
}
ADDRESS_REMAP_FUNC(0)
ADDRESS_REMAP_FUNC(1)
ADDRESS_REMAP_FUNC(2)
ADDRESS_REMAP_FUNC(3)
ADDRESS_REMAP_FUNC(4)
ADDRESS_REMAP_FUNC(5)
ADDRESS_REMAP_FUNC(6)
ADDRESS_REMAP_FUNC(7)
ADDRESS_REMAP_FUNC(8)
ADDRESS_REMAP_FUNC(9)
ADDRESS_REMAP_FUNC(10)
ADDRESS_REMAP_FUNC(11)
ADDRESS_REMAP_FUNC(12)
ADDRESS_REMAP_FUNC(13)
ADDRESS_REMAP_FUNC(14)
ADDRESS_REMAP_FUNC(15)
static uint32_t (*address_remap_funcs[16])(ega_t *ega, uint32_t in_addr) =
{
address_remap_func_0,
address_remap_func_1,
address_remap_func_2,
address_remap_func_3,
address_remap_func_4,
address_remap_func_5,
address_remap_func_6,
address_remap_func_7,
address_remap_func_8,
address_remap_func_9,
address_remap_func_10,
address_remap_func_11,
address_remap_func_12,
address_remap_func_13,
address_remap_func_14,
address_remap_func_15
};
void ega_recalc_remap_func(ega_t *ega)
{
int func_nr;
if (ega->crtc[0x14] & 0x40)
func_nr = VAR_DWORD_MODE;
else if (ega->crtc[0x17] & 0x40)
func_nr = VAR_BYTE_MODE;
else if (ega->crtc[0x17] & 0x20)
func_nr = VAR_WORD_MODE_MA15;
else
func_nr = VAR_WORD_MODE_MA13;
if (!(ega->crtc[0x17] & 0x01))
func_nr |= VAR_ROW0_MA13;
if (!(ega->crtc[0x17] & 0x02))
func_nr |= VAR_ROW1_MA14;
ega->remap_required = (func_nr != 0);
ega->remap_func = address_remap_funcs[func_nr];
}
#endif /*VIDEO_RENDER_REMAP_H*/