276 lines
6.1 KiB
C
276 lines
6.1 KiB
C
/*
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* 86Box A hypervisor and IBM PC system emulator that specializes in
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* running old operating systems and software designed for IBM
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* PC systems and compatibles from 1981 through fairly recent
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* system designs based on the PCI bus.
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*
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* This file is part of the 86Box distribution.
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*
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* Emulation of the TI CF62011 SVGA chip.
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*
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* This chip was used in several of IBM's later machines, such
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* as the PS/1 Model 2121, and a number of PS/2 models. As noted
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* in an article on Usenet:
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*
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* "In the early 90s IBM looked for some cheap VGA card to
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* substitute the (relatively) expensive XGA-2 adapter for
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* *servers*, where the primary purpose is supervision of the
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* machine rather than real *work* with it in Hi-Res. It was
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* just to supply a base video, where a XGA-2 were a waste of
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* potential. They had a contract with TI for some DSPs in
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* multimedia already (the MWave for instance is based on
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* TI-DSPs as well as many Thinkpad internal chipsets) and TI
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* offered them a rather cheap – and inexpensive – chipset
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* and combined it with a cheap clock oscillator and an Inmos
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* RAMDAC. That chipset was already pretty much outdated at
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* that time but IBM decided it would suffice for that low
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* end purpose.
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*
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* Driver support was given under DOS and OS/2 only for base
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* functions like selection of the vertical refresh and few
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* different modes only. Not even the Win 3.x support has
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* been finalized. Technically the adapter could do better
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* than VGA, but its video BIOS is largely undocumented and
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* intentionally crippled down to a few functions."
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*
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* This chip is reportedly the same one as used in the MCA
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* IBM SVGA Adapter/A (ID 090EEh), which mostly had faster
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* VRAM and RAMDAC. The VESA DOS graphics driver for that
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* card can be used: m95svga.exe
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*
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* The controller responds at ports in the range 0x2100-0x210F,
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* which are the same as the XGA. It supports up to 1MB of VRAM,
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* but we lock it down to 512K. The PS/1 2122 had 256K.
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*
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*
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*
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* Authors: Sarah Walker, <http://pcem-emulator.co.uk/>
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* Miran Grca, <mgrca8@gmail.com>
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* Fred N. van Kempen, <decwiz@yahoo.com>
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*
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* Copyright 2008-2018 Sarah Walker.
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* Copyright 2016-2018 Miran Grca.
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* Copyright 2017,2018 Fred N. van Kempen.
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*/
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#include <stdio.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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#include <wchar.h>
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#include <86box/86box.h>
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#include <86box/io.h>
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#include <86box/timer.h>
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#include <86box/mem.h>
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#include <86box/rom.h>
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#include <86box/device.h>
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#include <86box/video.h>
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#include <86box/vid_svga.h>
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typedef struct {
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svga_t svga;
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rom_t bios_rom;
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int enabled;
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uint32_t vram_size;
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uint8_t banking;
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uint8_t reg_2100;
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uint8_t reg_210a;
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} tivga_t;
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static video_timings_t timing_ti_cf62011 = {VIDEO_ISA, 6, 8,16, 6, 8,16};
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static void
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vid_out(uint16_t addr, uint8_t val, void *priv)
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{
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tivga_t *ti = (tivga_t *)priv;
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svga_t *svga = &ti->svga;
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uint8_t old;
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#if 0
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if (((addr & 0xfff0) == 0x03d0 || (addr & 0xfff0) == 0x03b0) &&
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!(svga->miscout & 1)) addr ^= 0x60;
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#endif
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switch (addr) {
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case 0x0102:
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ti->enabled = (val & 0x01);
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return;
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case 0x03d4:
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svga->crtcreg = val & 0x3f;
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return;
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case 0x03d5:
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if (svga->crtcreg & 0x20)
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return;
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if ((svga->crtcreg < 7) && (svga->crtc[0x11] & 0x80))
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return;
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if ((svga->crtcreg == 7) && (svga->crtc[0x11] & 0x80))
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val = (svga->crtc[7] & ~0x10) | (val & 0x10);
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old = svga->crtc[svga->crtcreg];
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svga->crtc[svga->crtcreg] = val;
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if (old != val) {
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if (svga->crtcreg < 0xe || svga->crtcreg > 0x10) {
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svga->fullchange = changeframecount;
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svga_recalctimings(svga);
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}
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}
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break;
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case 0x2100:
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ti->reg_2100 = val;
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if ((val & 7) < 4)
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svga->read_bank = svga->write_bank = 0;
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else
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svga->read_bank = svga->write_bank = (ti->banking & 0x7) * 0x10000;
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break;
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case 0x2108:
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if ((ti->reg_2100 & 7) >= 4)
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svga->read_bank = svga->write_bank = (val & 0x7) * 0x10000;
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ti->banking = val;
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break;
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case 0x210a:
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ti->reg_210a = val;
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break;
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}
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svga_out(addr, val, svga);
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}
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static uint8_t
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vid_in(uint16_t addr, void *priv)
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{
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tivga_t *ti = (tivga_t *)priv;
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svga_t *svga = &ti->svga;
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uint8_t ret;
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#if 0
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if (((addr & 0xfff0) == 0x03d0 || (addr & 0xfff0) == 0x03b0) &&
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!(svga->miscout & 1)) addr ^= 0x60;
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#endif
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switch (addr) {
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case 0x0100:
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ret = 0xfe;
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break;
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case 0x0101:
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ret = 0xe8;
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break;
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case 0x0102:
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ret = ti->enabled;
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break;
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case 0x03d4:
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ret = svga->crtcreg;
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break;
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case 0x03d5:
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if (svga->crtcreg & 0x20)
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ret = 0xff;
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else
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ret = svga->crtc[svga->crtcreg];
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break;
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case 0x2100:
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ret = ti->reg_2100;
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break;
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case 0x2108:
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ret = ti->banking;
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break;
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case 0x210a:
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ret = ti->reg_210a;
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break;
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default:
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ret = svga_in(addr, svga);
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break;
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}
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return(ret);
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}
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static void
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vid_speed_changed(void *priv)
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{
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tivga_t *ti = (tivga_t *)priv;
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svga_recalctimings(&ti->svga);
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}
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static void
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vid_force_redraw(void *priv)
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{
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tivga_t *ti = (tivga_t *)priv;
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ti->svga.fullchange = changeframecount;
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}
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static void
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vid_close(void *priv)
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{
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tivga_t *ti = (tivga_t *)priv;
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svga_close(&ti->svga);
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free(ti);
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}
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static void *
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vid_init(const device_t *info)
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{
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tivga_t *ti;
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/* Allocate control block and initialize. */
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ti = (tivga_t *)malloc(sizeof(tivga_t));
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memset(ti, 0x00, sizeof(tivga_t));
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/* Set amount of VRAM in KB. */
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if (info->local == 0)
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ti->vram_size = device_get_config_int("vram_size");
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else
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ti->vram_size = info->local;
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video_inform(VIDEO_FLAG_TYPE_SPECIAL, &timing_ti_cf62011);
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svga_init(info, &ti->svga, ti,
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ti->vram_size<<10,
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NULL, vid_in, vid_out, NULL, NULL);
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io_sethandler(0x0100, 2, vid_in, NULL, NULL, NULL, NULL, NULL, ti);
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io_sethandler(0x03c0, 32, vid_in, NULL, NULL, vid_out, NULL, NULL, ti);
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io_sethandler(0x2100, 16, vid_in, NULL, NULL, vid_out, NULL, NULL, ti);
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ti->svga.bpp = 8;
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ti->svga.miscout = 1;
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return(ti);
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}
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const device_t ibm_ps1_2121_device = {
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"IBM PS/1 Model 2121 SVGA",
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DEVICE_ISA,
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512,
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vid_init, vid_close, NULL,
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NULL,
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vid_speed_changed,
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vid_force_redraw,
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NULL
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};
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