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More fixes to the mode switching of the ATI/IBM 8514/A compatibles (June 28th, 2025)

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The mode switching phase now takes account of the display enable/reset bits of port 0x22e8 (bits 5-6). Fixes Solaris mode switching and keeps everything else happy (I hope).
This commit is contained in:
TC1995
2025-06-28 20:55:14 +02:00
parent d15e062c83
commit 5fbcbde4ba
4 changed files with 158 additions and 110 deletions
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9
src/include/86box/vid_8514a.h
View File

@@ -37,6 +37,13 @@ typedef enum {
EXTENSIONS_MAX
} ibm8514_extensions_t;
typedef enum {
VGA_MODE = 0,
IBM_MODE,
ATI_MODE,
MODE_MAX
} ibm8514_mode_t;
typedef struct hwcursor8514_t {
int ena;
int x;
@@ -202,6 +209,7 @@ typedef struct ibm8514_t {
int split;
int h_disp;
int h_total;
int h_sync_start;
int h_sync_width;
int h_disp_time;
int rowoffset;
@@ -260,6 +268,7 @@ typedef struct ibm8514_t {
int ext_pitch;
int ext_crt_pitch;
ibm8514_extensions_t extensions;
ibm8514_mode_t mode;
int onboard;
int linear;
uint32_t vram_amount;

12
src/video/vid_8514a.c
View File

@@ -911,8 +911,10 @@ ibm8514_accel_in(uint16_t port, svga_t *svga)
switch (port) {
case 0x2e8:
if (dev->vc == dev->v_syncstart)
temp |= 0x02;
if (dev->vc == dev->v_syncstart) {
if (dev->accel.advfunc_cntl & 0x04)
temp |= 0x02;
}
ibm8514_log("Read: Display Status1=%02x.\n", temp);
break;
@@ -3817,7 +3819,7 @@ ibm8514_recalctimings(svga_t *svga)
} else {
if (dev->on) {
dev->hdisp = (dev->hdisped + 1) << 3;
dev->h_total = dev->htotal + 1;
dev->h_total = (dev->htotal + 1) << 3;
if (dev->h_total == 1) /*Default to 1024x768 87hz 8514/A htotal timings if it goes to 0.*/
dev->h_total = 0x9e;
@@ -3827,10 +3829,14 @@ ibm8514_recalctimings(svga_t *svga)
dev->vdisp += 2;
dev->v_total = dev->v_total_reg + 1;
if (dev->v_total == 1)
dev->v_total = 0x0669;
if (dev->interlace)
dev->v_total >>= 1;
dev->v_syncstart = dev->v_sync_start + 1;
if (dev->v_syncstart == 1)
dev->v_syncstart = 0x0601;
if (dev->interlace)
dev->v_syncstart >>= 1;

169
src/video/vid_ati_mach8.c
View File

@@ -2699,93 +2699,80 @@ ati_render_32bpp(svga_t *svga)
}
/*The situation is the following:
When ATI mode is selected, allow complete auto-detection.
But when 8514/A mode is selected, allow detection based on the shadow register sets.
When ATI (0x4aee) mode is selected, allow complete auto-detection.
When 8514/A (0x4ae8) mode is selected, allow detection based on the shadow register sets.
*/
static void
mach_set_resolution(mach_t *mach, svga_t *svga)
{
ibm8514_t *dev = (ibm8514_t *) svga->dev8514;
int ret = 0;
ibm8514_t *dev = (ibm8514_t *) svga->dev8514;
dev->h_total = dev->htotal + 1;
if (dev->h_total == 1) /*Default to 1024x768 87hz 8514/A htotal timings if it goes to 0.*/
dev->h_total = 0x9e;
dev->h_total = (dev->htotal + 1) << 3;
if (dev->h_total == 8) /*Default to 1024x768 87hz 8514/A htotal timings if it goes to 0.*/
dev->h_total = 0x9e << 3;
dev->hdisp = (dev->hdisped + 1) << 3;
dev->vdisp = (dev->v_disp + 1) >> 1;
if ((dev->vdisp == 478) || (dev->vdisp == 598) || (dev->vdisp == 766) || (dev->vdisp == 1022))
if ((dev->vdisp == 478) || (dev->vdisp == 598) || (dev->vdisp == 766) || (dev->vdisp == 898) || (dev->vdisp == 1022))
dev->vdisp += 2;
dev->v_total = dev->v_total_reg + 1;
if (dev->v_total == 1)
dev->v_total = 0x0669;
dev->v_syncstart = dev->v_sync_start + 1;
if (dev->v_syncstart == 1)
dev->v_syncstart = 0x0601;
mach_log("VSYNCSTART=%d, VTOTAL=%d, interlace=%02x, vdisp=%d.\n", dev->v_syncstart, dev->v_total, dev->interlace, dev->vdisp);
mach_log("ATI Mode: set=%02x, dispcntl=%02x, h_total=%d, hdisp=%d, vdisp=%d, v_total=%04x, v_syncstart=%04x, hsync_start=%d, hsync_width=%d, clocksel=%02x, advancedcntl=%02x.\n", mach->shadow_set & 0x03, dev->disp_cntl, dev->h_total, dev->hdisp, dev->vdisp, dev->v_total, dev->v_syncstart, dev->hsync_start, dev->hsync_width, mach->accel.clock_sel & 0xff, dev->accel.advfunc_cntl & 0x05);
if ((dev->disp_cntl >> 5) == 1) { /*Enable the 8514/A subsystem and set modes according to the shadow sets if needed.*/
switch (mach->shadow_set & 0x03) {
case 0x01:
if (!(dev->accel.advfunc_cntl & 0x04)) {
dev->h_total = 0x64 << 3;
dev->hdisp = 640;
dev->vdisp = 480;
dev->v_total = 0x0419;
dev->v_syncstart = 0x03d7;
}
break;
case 0x02:
if (dev->accel.advfunc_cntl & 0x04) {
dev->h_total = 0x9e << 3;
dev->hdisp = 1024;
dev->vdisp = 768;
dev->v_total = 0x0669;
dev->v_syncstart = 0x0601;
}
break;
if (!ATI_MACH32) {
if ((mach->accel.clock_sel & 0x01) &&
!(dev->accel.advfunc_cntl & 0x01))
ret = 2;
else if ((dev->accel.advfunc_cntl & 0x01) &&
!(mach->accel.clock_sel & 0x01))
ret = 1;
else if ((!(dev->accel.advfunc_cntl & 0x01) && (mach->old_on1 & 0x01)) ||
(!(mach->accel.clock_sel & 0x01) && (mach->old_on2 & 0x01)))
ret = 0;
} else {
if ((mach->accel.clock_sel & 0x01) && !(mach->old_on2 & 0x01) &&
!(dev->accel.advfunc_cntl & 0x01))
ret = 2;
else if ((dev->accel.advfunc_cntl & 0x01) && !(mach->old_on1 & 0x01) &&
!(mach->accel.clock_sel & 0x01))
ret = 1;
else if ((!(dev->accel.advfunc_cntl & 0x01) && (mach->old_on1 & 0x01)) ||
(!(mach->accel.clock_sel & 0x01) && (mach->old_on2 & 0x01)))
ret = 0;
}
if (ret) {
if (ret == 2)
svga_recalctimings(svga);
else {
switch (mach->shadow_set & 0x03) {
case 0x00:
if (mach->crt_resolution)
svga_recalctimings(svga);
else {
if (dev->accel.advfunc_cntl & 0x04) {
if (dev->hdisp == 640) {
dev->hdisp = 1024;
dev->vdisp = 768;
mach_log("1024x768.\n");
}
} else {
if (dev->hdisp == 1024) {
dev->hdisp = 640;
dev->vdisp = 480;
mach_log("640x480.\n");
}
}
svga_recalctimings(svga);
}
break;
case 0x01:
mach->crt_resolution = 0x01;
break;
case 0x02:
mach->crt_resolution = 0x02;
break;
default:
break;
default:
break;
}
svga_recalctimings(svga);
} else if ((dev->disp_cntl >> 5) == 2) { /*Reset 8514/A to defaults if needed.*/
if (dev->accel.advfunc_cntl & 0x04) {
if (dev->hdisp == 640) {
dev->h_total = 0x9e << 3;
dev->hdisp = 1024;
dev->vdisp = 768;
dev->v_total = 0x0669;
dev->v_syncstart = 0x0601;
svga_recalctimings(svga);
}
} else {
if (dev->hdisp == 1024) {
dev->h_total = 0x64 << 3;
dev->hdisp = 640;
dev->vdisp = 480;
dev->v_total = 0x0419;
dev->v_syncstart = 0x03d7;
svga_recalctimings(svga);
}
}
} else
} else /*No change (type 0) or reset type 3.*/
svga_recalctimings(svga);
mach_log("Shadow set ATI=%x, shadow set 8514/A and on1=%x, on2=%x, resolution h=%d, v=%d, vtotal=%d, vsyncstart=%d, crtres=%d, ret=%d, actual passthrough=%x.\n", mach->shadow_set & 0x03, dev->accel.advfunc_cntl & 0x05, mach->accel.clock_sel & 0x01, dev->hdisp, dev->vdisp, dev->v_total, dev->v_syncstart, mach->crt_resolution, ret, dev->on);
}
void
@@ -2845,7 +2832,7 @@ ati8514_recalctimings(svga_t *svga)
svga->render8514 = ibm8514_render_8bpp;
} else
mach->crt_resolution = 0;
dev->mode = VGA_MODE;
}
static void
@@ -2899,9 +2886,9 @@ mach_recalctimings(svga_t *svga)
svga->ati_4color = 0;
}
mach_log("ON=%d, override=%d, gelo=%04x, gehi=%04x, vgahdisp=%d.\n", dev->on, svga->override, mach->accel.ge_offset_lo, mach->accel.ge_offset_hi, svga->hdisp);
mach_log("ON=%d, override=%d, gelo=%04x, gehi=%04x, crtlo=%04x, crthi=%04x, vgahdisp=%d.\n", dev->on, svga->override, mach->accel.ge_offset_lo, mach->accel.ge_offset_hi, mach->accel.crt_offset_lo, mach->accel.crt_offset_hi, svga->hdisp);
if (dev->on) {
dev->memaddr_latch = 0; /*(mach->accel.crt_offset_lo | (mach->accel.crt_offset_hi << 16)) << 2;*/
dev->memaddr_latch = 0; /*(mach->accel.crt_offset_lo | (mach->accel.crt_offset_hi << 16)) << 2;*/
dev->interlace = !!(dev->disp_cntl & 0x10);
dev->pitch = dev->ext_pitch;
dev->rowoffset = dev->ext_crt_pitch;
@@ -2949,8 +2936,8 @@ mach_recalctimings(svga_t *svga)
if (ATI_MACH32) {
switch ((mach->shadow_set >> 8) & 0x03) {
case 0x00:
mach->accel.src_pitch = ((mach->accel.ge_pitch & 0xff) << 3);
mach->accel.dst_pitch = ((mach->accel.ge_pitch & 0xff) << 3);
mach->accel.src_pitch = dev->pitch;
mach->accel.dst_pitch = dev->pitch;
mach->accel.src_ge_offset = (mach->accel.ge_offset_lo | (mach->accel.ge_offset_hi << 16));
mach->accel.dst_ge_offset = (mach->accel.ge_offset_lo | (mach->accel.ge_offset_hi << 16));
if (dev->bpp) {
@@ -2972,7 +2959,7 @@ mach_recalctimings(svga_t *svga)
dev->accel.dst_ge_offset = mach->accel.dst_ge_offset;
break;
case 0x01:
mach->accel.dst_pitch = ((mach->accel.ge_pitch & 0xff) << 3);
mach->accel.dst_pitch = dev->pitch;
mach->accel.dst_ge_offset = (mach->accel.ge_offset_lo | (mach->accel.ge_offset_hi << 16));
if (dev->bpp)
mach->accel.dst_ge_offset <<= 1;
@@ -2987,7 +2974,7 @@ mach_recalctimings(svga_t *svga)
dev->accel.dst_ge_offset = mach->accel.dst_ge_offset;
break;
case 0x02:
mach->accel.src_pitch = ((mach->accel.ge_pitch & 0xff) << 3);
mach->accel.src_pitch = dev->pitch;
mach->accel.src_ge_offset = (mach->accel.ge_offset_lo | (mach->accel.ge_offset_hi << 16));
if (dev->bpp)
mach->accel.src_ge_offset <<= 1;
@@ -3067,7 +3054,7 @@ mach_recalctimings(svga_t *svga)
svga->render8514 = ibm8514_render_8bpp;
}
} else {
mach->crt_resolution = 0;
dev->mode = VGA_MODE;
if (!svga->scrblank && (svga->crtc[0x17] & 0x80) && svga->attr_palette_enable) {
mach_log("GDCREG5=%02x, ATTR10=%02x, ATI B0 bit 5=%02x, ON=%d.\n",
svga->gdcreg[5] & 0x60, svga->attrregs[0x10] & 0x40, mach->regs[0xb0] & 0x20, dev->on);
@@ -3240,7 +3227,7 @@ mach_accel_out_fifo(mach_t *mach, svga_t *svga, ibm8514_t *dev, uint16_t port, u
mach_log("ATI 8514/A: V_DISP write 16E8=%d, vdisp2=%d.\n", dev->v_disp, dev->v_disp2);
mach_log("ATI 8514/A: (0x%04x): vdisp=0x%02x.\n", port, val);
} else {
if ((mach->accel.clock_sel & 0x01) || (!(mach->accel.clock_sel & 0x01) && (mach->shadow_set & 0x03))) { /*For 8514/A mode, take the shadow sets into account.*/
if ((mach->accel.clock_sel & 0x01) || (!(mach->accel.clock_sel & 0x01) && (mach->shadow_set & 0x03))) { /*For 8514/A mode, take the shadow sets into account.*/
if (!(mach->shadow_cntl & 0x20)) {
WRITE8(port, dev->v_disp, val);
dev->v_disp &= 0x1fff;
@@ -3265,7 +3252,7 @@ mach_accel_out_fifo(mach_t *mach, svga_t *svga, ibm8514_t *dev, uint16_t port, u
case 0x1ae8:
if (len == 2) {
if ((mach->accel.clock_sel & 0x01) || (!(mach->accel.clock_sel & 0x01) && (mach->shadow_set & 0x03))) { /*For 8514/A mode, take the shadow sets into account.*/
if ((mach->accel.clock_sel & 0x01) || (!(mach->accel.clock_sel & 0x01) && (mach->shadow_set & 0x03))) { /*For 8514/A mode, take the shadow sets into account.*/
if (!(mach->shadow_cntl & 0x10) && val) {
dev->v_sync_start = val;
dev->v_sync_start &= 0x1fff;
@@ -3274,7 +3261,7 @@ mach_accel_out_fifo(mach_t *mach, svga_t *svga, ibm8514_t *dev, uint16_t port, u
mach_log("ATI 8514/A: V_SYNCSTART write 1AE8 = %d\n", dev->v_syncstart);
mach_log("ATI 8514/A: (0x%04x): vsyncstart=0x%02x.\n", port, val);
} else {
if ((mach->accel.clock_sel & 0x01) || (!(mach->accel.clock_sel & 0x01) && (mach->shadow_set & 0x03))) { /*For 8514/A mode, take the shadow sets into account.*/
if ((mach->accel.clock_sel & 0x01) || (!(mach->accel.clock_sel & 0x01) && (mach->shadow_set & 0x03))) { /*For 8514/A mode, take the shadow sets into account.*/
if (!(mach->shadow_cntl & 0x10)) {
WRITE8(port, dev->v_sync_start, val);
dev->v_sync_start &= 0x1fff;
@@ -3285,7 +3272,7 @@ mach_accel_out_fifo(mach_t *mach, svga_t *svga, ibm8514_t *dev, uint16_t port, u
break;
case 0x1ae9:
if (len == 1) {
if ((mach->accel.clock_sel & 0x01) || (!(mach->accel.clock_sel & 0x01) && (mach->shadow_set & 0x03))) { /*For 8514/A mode, take the shadow sets into account.*/
if ((mach->accel.clock_sel & 0x01) || (!(mach->accel.clock_sel & 0x01) && (mach->shadow_set & 0x03))) { /*For 8514/A mode, take the shadow sets into account.*/
if (!(mach->shadow_cntl & 0x10)) {
WRITE8(port, dev->v_sync_start, val >> 8);
dev->v_sync_start &= 0x1fff;
@@ -3334,7 +3321,6 @@ mach_accel_out_fifo(mach_t *mach, svga_t *svga, ibm8514_t *dev, uint16_t port, u
case 0x4ae8:
case 0x4ae9:
mach->old_on1 = dev->accel.advfunc_cntl & 0x01;
WRITE8(port, dev->accel.advfunc_cntl, val);
if (len == 2) {
WRITE8(port + 1, dev->accel.advfunc_cntl, val >> 8);
@@ -3348,6 +3334,7 @@ mach_accel_out_fifo(mach_t *mach, svga_t *svga, ibm8514_t *dev, uint16_t port, u
}
}
dev->mode = IBM_MODE;
mach_log("[%04X:%08X]: ATI 8514/A: (0x%04x): ON=%d, valxor=%x, shadow crt=%x, hdisp=%d, vdisp=%d, extmode=%02x, accelbpp=%d, crt=%d, crtres=%d.\n",
CS, cpu_state.pc, port, val & 0x01, dev->on, dev->accel.advfunc_cntl & 0x04, dev->hdisp, dev->vdisp, mach->regs[0xb0] & 0x20, dev->accel_bpp, dev->_8514crt, mach->crt_resolution);
@@ -3686,7 +3673,11 @@ mach_accel_out_fifo(mach_t *mach, svga_t *svga, ibm8514_t *dev, uint16_t port, u
} else
dev->_8514crt = 1;
mach_set_resolution(mach, svga);
if (dev->mode != VGA_MODE)
mach_set_resolution(mach, svga);
else
svga_recalctimings(svga);
if (ATI_GRAPHICS_ULTRA || ATI_MACH32)
mach32_updatemapping(mach, svga);
@@ -3779,13 +3770,15 @@ mach_accel_out_fifo(mach_t *mach, svga_t *svga, ibm8514_t *dev, uint16_t port, u
case 0x4aee:
case 0x4aef:
mach->old_on2 = mach->accel.clock_sel & 0x01;
WRITE8(port, mach->accel.clock_sel, val);
if (len == 2) {
WRITE8(port + 1, mach->accel.clock_sel, val >> 8);
}
dev->on = mach->accel.clock_sel & 0x01;
if (!(dev->accel.advfunc_cntl & 0x01))
dev->on = mach->accel.clock_sel & 0x01;
dev->vendor_mode = 1;
dev->mode = ATI_MODE;
mach_log("[%04X:%08X]: ATI 8514/A: (0x%04x): ON=%d, val=%04x, xor=%d, hdisp=%d, vdisp=%d, accelbpp=%d.\n",
CS, cpu_state.pc, port, mach->accel.clock_sel & 0x01, val, dev->on, dev->hdisp, dev->vdisp, dev->accel_bpp);
@@ -3937,7 +3930,11 @@ mach_accel_out_fifo(mach_t *mach, svga_t *svga, ibm8514_t *dev, uint16_t port, u
}
svga_set_ramdac_type(svga, !!(mach->accel.ext_ge_config & 0x4000));
mach_log("ATI 8514/A: (0x%04x) Extended Configuration=%04x, val=%04x.\n", port, mach->accel.ext_ge_config, val);
mach_set_resolution(mach, svga);
if (dev->mode != VGA_MODE)
mach_set_resolution(mach, svga);
else
svga_recalctimings(svga);
mach32_updatemapping(mach, svga);
} else
ati_eeprom_write(&mach->eeprom, !!(mach->accel.ext_ge_config & 0x04), !!(mach->accel.ext_ge_config & 0x02), !!(mach->accel.ext_ge_config & 0x01));
@@ -7195,6 +7192,7 @@ mach8_init(const device_t *info)
mach_io_set(mach);
mach->accel.cmd_type = -2;
dev->accel.cmd_back = 1;
dev->mode = IBM_MODE;
if (ATI_MACH32) {
svga->decode_mask = (4 << 20) - 1;
@@ -7256,6 +7254,7 @@ ati8514_init(svga_t *svga, void *ext8514, void *dev8514)
dev->disp_cntl = 0x33;
mach->accel.clock_sel = 0x1c;
dev->accel.cmd_back = 1;
dev->mode = IBM_MODE;
io_sethandler(0x02ea, 4, ati8514_in, NULL, NULL, ati8514_out, NULL, NULL, svga);
ati8514_io_set(svga);

78
src/video/vid_svga.c
View File

@@ -977,29 +977,57 @@ svga_recalctimings(svga_t *svga)
}
}
#ifdef TBD
#if TBD
if (ibm8514_active && (svga->dev8514 != NULL)) {
if (dev->on) {
uint32_t dot8514 = dev->h_blankstart;
uint32_t adj_dot8514 = dev->h_blankstart;
uint32_t eff_mask8514 = 0x0000001f;
dev->hblank_sub = 0;
uint32_t _8514_dot = dev->h_sync_start;
uint32_t _8514_adj_dot = dev->h_sync_start;
uint32_t _8514_eff_mask = (dev->h_blank_end_val & ~0x0000001f) ? dev->h_blank_end_mask : 0x0000001f;
dev->h_blank_sub = 0;
while (adj_dot8514 < (dev->h_total << 1)) {
if (dot8514 == dev->h_total)
dot8514 = 0;
mach_log("8514/A: HDISP=%d, HDISPED=%d, Blank: %04i-%04i, Total: %04i, "
"Mask: %02X, ADJ_DOT=%04i.\n", dev->hdisp, (dev->hdisped + 1) << 3,
dev->h_sync_start, dev->h_blank_end_val,
dev->h_total, _8514_eff_mask, _8514_adj_dot);
if (adj_dot8514 >= dev->h_total)
dev->hblank_sub++;
while (_8514_adj_dot < (dev->h_total << 1)) {
if (_8514_dot == dev->h_total)
_8514_dot = 0;
if ((dot8514 & eff_mask8514) == (dev->h_blank_end_val & eff_mask8514))
if (_8514_adj_dot >= dev->h_total)
dev->h_blank_sub++;
mach_log("8514/A: Loop: adjdot=%d, htotal=%d, dotmask=%02x, "
"hblankendvalmask=%02x, blankendval=%02x.\n", adj_dot,
dev->h_total, _8514_dot & _8514_eff_mask, dev->h_blank_end_val & _8514_eff_mask,
dev->h_blank_end_val);
if ((_8514_dot & _8514_eff_mask) == (dev->h_blank_end_val & _8514_eff_mask))
break;
dot8514++;
adj_dot8514++;
_8514_dot++;
_8514_adj_dot++;
}
dev->h_disp -= dev->hblank_sub;
uint32_t _8514_hd = dev->hdisp;
dev->hdisp -= dev->h_blank_sub;
svga->left_overscan = svga->x_add = (dev->h_total - _8514_adj_dot - 1) << 3;
svga->monitor->mon_overscan_x = svga->x_add + (dev->h_sync_start << 3) - _8514_hd + 8;
svga->monitor->mon_overscan_x++;
if ((dev->hdisp >= 2048) || (svga->left_overscan < 0)) {
svga->left_overscan = svga->x_add = 0;
svga->monitor->mon_overscan_x = 0;
}
/* - 1 because + 1 but also - 2 to compensate for the + 2 added to vtotal above. */
svga->y_add = svga->vtotal - svga->vblankend - 1;
svga->monitor->mon_overscan_y = svga->y_add + abs(svga->vblankstart - svga->dispend);
if ((svga->dispend >= 2048) || (svga->y_add < 0)) {
svga->y_add = 0;
svga->monitor->mon_overscan_y = 0;
}
}
}
#endif
@@ -1194,18 +1222,24 @@ svga_recalctimings(svga_t *svga)
video_force_resize_set_monitor(1, svga->monitor_index);
svga->force_shifter_bypass = 0;
if (svga->hdisp == 320 && svga->dispend >= 400 && !svga->override && svga->render != svga_render_8bpp_clone_highres) {
svga->hdisp *= 2;
if (svga->render == svga_render_16bpp_highres) svga->render = svga_render_16bpp_lowres;
else if (svga->render == svga_render_15bpp_highres) svga->render = svga_render_15bpp_lowres;
else if (svga->render == svga_render_15bpp_mix_highres) svga->render = svga_render_15bpp_mix_lowres;
else if (svga->render == svga_render_24bpp_highres) svga->render = svga_render_24bpp_lowres;
else if (svga->render == svga_render_32bpp_highres) svga->render = svga_render_32bpp_lowres;
if ((svga->hdisp == 320) && (svga->dispend >= 400) && !svga->override && (svga->render != svga_render_8bpp_clone_highres)) {
svga->hdisp <<= 1;
if (svga->render == svga_render_16bpp_highres)
svga->render = svga_render_16bpp_lowres;
else if (svga->render == svga_render_15bpp_highres)
svga->render = svga_render_15bpp_lowres;
else if (svga->render == svga_render_15bpp_mix_highres)
svga->render = svga_render_15bpp_mix_lowres;
else if (svga->render == svga_render_24bpp_highres)
svga->render = svga_render_24bpp_lowres;
else if (svga->render == svga_render_32bpp_highres)
svga->render = svga_render_32bpp_lowres;
else if (svga->render == svga_render_8bpp_highres) {
svga->render = svga_render_8bpp_lowres;
svga->force_shifter_bypass = 1;
}
else svga->hdisp /= 2;
else
svga->hdisp >>= 1;
}
}