246 lines
8 KiB
C
246 lines
8 KiB
C
/*Oak OTI037 emulation*/
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#include <stdlib.h>
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#include "ibm.h"
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#include "device.h"
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#include "io.h"
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#include "mem.h"
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#include "rom.h"
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#include "video.h"
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#include "vid_oti037.h"
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#include "vid_svga.h"
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typedef struct oti037_t
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{
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svga_t svga;
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rom_t bios_rom;
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int index;
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uint8_t regs[32];
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uint8_t enable_register;
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} oti037_t;
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void oti037_out(uint16_t addr, uint8_t val, void *p)
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{
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oti037_t *oti037 = (oti037_t *)p;
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svga_t *svga = &oti037->svga;
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uint8_t old;
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uint8_t idx;
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if (!(oti037->enable_register & 1) && addr != 0x3C3)
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return;
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if ((((addr&0xFFF0) == 0x3D0 || (addr&0xFFF0) == 0x3B0) && addr < 0x3de) && !(svga->miscout & 1)) addr ^= 0x60; // mono / color addr selection
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// pclog("oti037_out : %04X %02X %02X %i ", addr, val, ram[0x489], ins);
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// pclog(" %04X:%04X\n", CS,cpu_state.pc);
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switch (addr)
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{
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case 0x3C3:
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oti037->enable_register = val & 1;
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return;
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case 0x3D4:
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svga->crtcreg = val /*& 31*/; // fixme: bios wants to set the test bit?
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return;
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case 0x3D5:
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if (((svga->crtcreg & 31) < 7) && (svga->crtc[0x11] & 0x80))
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return;
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if (((svga->crtcreg & 31) == 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 & 31];
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svga->crtc[svga->crtcreg & 31] = val;
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if (old != val)
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{
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if ((svga->crtcreg & 31) < 0xE || (svga->crtcreg & 31) > 0x10)
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{
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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 0x3DE:
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oti037->index = val /*& 0x1f*/;
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return;
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case 0x3DF:
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idx = oti037->index & 0x1f;
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oti037->regs[idx] = val;
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switch (idx)
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{
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case 0xD:
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if (val & 0x80)
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mem_mapping_disable(&svga->mapping);
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else
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mem_mapping_enable(&svga->mapping);
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break;
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case 0x11:
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svga->read_bank = (val & 0xf) * 65536;
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svga->write_bank = (val >> 4) * 65536;
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break;
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}
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return;
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}
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svga_out(addr, val, svga);
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}
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uint8_t oti037_in(uint16_t addr, void *p)
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{
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oti037_t *oti037 = (oti037_t *)p;
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svga_t *svga = &oti037->svga;
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uint8_t temp;
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if (!(oti037->enable_register & 1) && addr != 0x3C3)
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return 0xff;
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if ((((addr&0xFFF0) == 0x3D0 || (addr&0xFFF0) == 0x3B0) && addr < 0x3de) && !(svga->miscout & 1)) addr ^= 0x60; // mono / color addr selection
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// if (addr != 0x3da && addr != 0x3ba) pclog("oti037_in : %04X ", addr);
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switch (addr)
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{
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case 0x3C3:
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temp = oti037->enable_register;
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break;
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case 0x3D4:
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temp = svga->crtcreg;
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break;
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case 0x3D5:
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temp = svga->crtc[svga->crtcreg & 31];
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break;
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case 0x3DA:
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svga->attrff = 0;
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/*The OTI-037C BIOS waits for bits 0 and 3 in 0x3da to go low, then reads 0x3da again
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and expects the diagnostic bits to equal the current border colour. As I understand
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it, the 0x3da active enable status does not include the border time, so this may be
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an area where OTI-037C is not entirely VGA compatible.*/
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svga->cgastat &= ~0x30;
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/* copy color diagnostic info from the overscan color register */
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switch (svga->attrregs[0x12] & 0x30)
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{
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case 0x00: /* P0 and P2 */
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if (svga->attrregs[0x11] & 0x01)
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svga->cgastat |= 0x10;
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if (svga->attrregs[0x11] & 0x04)
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svga->cgastat |= 0x20;
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break;
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case 0x10: /* P4 and P5 */
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if (svga->attrregs[0x11] & 0x10)
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svga->cgastat |= 0x10;
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if (svga->attrregs[0x11] & 0x20)
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svga->cgastat |= 0x20;
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break;
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case 0x20: /* P1 and P3 */
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if (svga->attrregs[0x11] & 0x02)
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svga->cgastat |= 0x10;
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if (svga->attrregs[0x11] & 0x08)
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svga->cgastat |= 0x20;
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break;
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case 0x30: /* P6 and P7 */
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if (svga->attrregs[0x11] & 0x40)
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svga->cgastat |= 0x10;
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if (svga->attrregs[0x11] & 0x80)
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svga->cgastat |= 0x20;
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break;
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}
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return svga->cgastat;
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case 0x3DE:
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temp = oti037->index;
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break;
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case 0x3DF:
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if ((oti037->index & 0x1f)==0x10) temp = 0x18;
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else temp = oti037->regs[oti037->index & 0x1f];
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break;
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default:
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temp = svga_in(addr, svga);
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break;
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}
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// if (addr != 0x3da && addr != 0x3ba) pclog("%02X %04X:%04X\n", temp, CS,cpu_state.pc);
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return temp;
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}
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void oti037_recalctimings(svga_t *svga)
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{
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oti037_t *oti037 = (oti037_t *)svga->p;
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if (oti037->regs[0x14] & 0x08) svga->ma_latch |= 0x10000;
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if (oti037->regs[0x0d] & 0x0c) svga->rowoffset <<= 1;
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svga->interlace = oti037->regs[0x14] & 0x80;
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}
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void *oti037_common_init(char *bios_fn, int vram_size)
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{
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oti037_t *oti037 = malloc(sizeof(oti037_t));
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memset(oti037, 0, sizeof(oti037_t));
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rom_init(&oti037->bios_rom, bios_fn, 0xc0000, 0x8000, 0x7fff, 0, MEM_MAPPING_EXTERNAL);
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svga_init(&oti037->svga, oti037, vram_size << 10,
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oti037_recalctimings,
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oti037_in, oti037_out,
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NULL,
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NULL);
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io_sethandler(0x03c0, 0x0020, oti037_in, NULL, NULL, oti037_out, NULL, NULL, oti037);
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oti037->svga.miscout = 1;
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oti037->regs[0] = 0x08; // fixme: bios wants to read this at index 0? this index is undocumented
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return oti037;
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}
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void *oti037_init()
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{
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return oti037_common_init("oti037/bios.bin", 256);
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}
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static int oti037_available()
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{
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return rom_present("oti037/bios.bin");
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}
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void oti037_close(void *p)
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{
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oti037_t *oti037 = (oti037_t *)p;
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svga_close(&oti037->svga);
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free(oti037);
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}
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void oti037_speed_changed(void *p)
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{
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oti037_t *oti037 = (oti037_t *)p;
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svga_recalctimings(&oti037->svga);
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}
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void oti037_force_redraw(void *p)
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{
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oti037_t *oti037 = (oti037_t *)p;
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oti037->svga.fullchange = changeframecount;
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}
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void oti037_add_status_info(char *s, int max_len, void *p)
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{
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oti037_t *oti037 = (oti037_t *)p;
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svga_add_status_info(s, max_len, &oti037->svga);
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}
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device_t oti037_device =
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{
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"Oak OTI-037",
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0,
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oti037_init,
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oti037_close,
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oti037_available,
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oti037_speed_changed,
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oti037_force_redraw,
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oti037_add_status_info
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};
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