source: buchla-68k/ram/scadv.c@ b28a12e

/*
   =============================================================================
        scadv.c -- MIDAS-VII -- move score 1 frame forward or backward
        Version 48 -- 1989-12-19 -- D.N. Lynx Crowe
   =============================================================================
*/

#undef  DEBUGGER        /* define to enable debug trace */

#undef  TRACEIT         /* define to enable step by step trace */

#include "ram.h"

#ifdef  TRACEIT
short   tracesw;
#endif

/* initialized stuff */

int16_t nbmoff = 3;
int16_t wrdoff = 3;

int16_t nbmasks[4] = {          /* nybble masks */

        0x000F,
        0x00F0,
        0x0F00,
        0xF000
};

/* 

*/

/*
   =============================================================================
        sc_adv() -- advance the score display 1 frame

        Note that the score display actually only moves every other frame,
        due to VSDD limitations, but it moves 2 pixels.
   =============================================================================
*/

void sc_adv(void)
{
        register int16_t masksl, maskpx, i;
        register uint16_t sword;
        register int32_t tl;
        register uint16_t *optr, *pptr, *fsl;
        uint16_t *qptr;
        uint16_t pscrl;

        DB_ENTR("sc_adv");

#ifdef TRACEIT
        if (tracesw) {

                printf("scadv ----------------------\n");
                SEctrl();
        }

        if (tracesw & 0x0001) {

                SCslice();
        }
#endif

        if (v_regs[5] & 0x0180)         /* make sure we're in bank 0 */
                vbank(0);

        tl = 128L;                      /* setup VSDD line increment */

        DB_CMNT("sc_adv - center ucslice");

        ucslice();                      /* update the center slice */

/* 

*/
        /* see if it's time to update VRAM from edges */

        if ((ndisp EQ 2) AND (soffset EQ ((sd EQ D_BAK) ? 0 : 3))) {

                if (sd EQ D_BAK) {      /* set source and target pointers */

                        fsl  = prvsl;
                        optr = saddr + wrdoff;

                } else {

                        fsl  = nxtsl;
                        optr = saddr + tl;
                }

                if (sbase > 28544) {            /* possible double update ? */

                        /* set target pointer #2 */

                        pptr = saddr - ((sd EQ D_BAK) ? 28542L : 28545L);

                        if (sbase < 28672) {    /* double update - right and left */

                                DB_CMNT("sc_adv - double update");

                                for (i = 224; i--; ) {

                                        sword = *fsl++; /* copy a slice word to the VSDD */
                                        *optr = sword;
                                        *pptr = sword;
                                        optr += tl;     /* advance the VSDD pointers */
                                        pptr += tl;
                                }

                        } else {                /* single update - left */

                                DB_CMNT("sc_adv - left update");

                                for (i = 224; i--; ) {

                                        *pptr = *fsl++;         /* copy a slice word to the VSDD */
                                        pptr += tl;             /* advance the VSDD pointers */
                                }
                        }
/* 

*/
                } else {                        /* single update - right */

                                DB_CMNT("sc_adv - right update");

                        for (i = 224; i--; ) {

                                *optr = *fsl++;         /* copy a slice word to the VSDD */
                                optr += tl;             /* advance the VSDD pointers */
                        }
                }

                optr  = nxtsl;  /* refresh update slices from constant slice */
                pptr  = cursl;
                qptr  = prvsl;
                fsl   = consl;

                for (i = 224; i--; ) {

                        sword = *fsl++;
                        *optr++ = sword;
                        *pptr++ = sword;
                        *qptr++ = sword;
                }

                DB_CMNT("sc_adv - slices refreshed");
        }

/* 

*/
        if (sd EQ D_FWD) {

                if (++soffset > 3) {                    /* advance scroll counter */

                        soffset = 0;                    /* roll over scroll counter */
                        ++saddr;                        /* advance VRAM address */

                        if (++sbase > 28672) {          /* advance scroll offset */

                                saddr = v_score;        /* roll over VRAM address */
                                sbase = 0;              /* roll over scroll offset */
                        }
                }

        } else {

                if (--soffset < 0) {                    /* decrement scroll counter */

                        soffset = 3;                    /* roll over scroll counter */
                        --saddr;                        /* advance VRAM address */

                        if (--sbase < 0) {              /* advance scroll offset */

                                saddr = v_score + 28672L;       /* roll over VRAM address */
                                sbase = 28672;          /* roll over scroll offset */
                        }
                }
        }
/* 

*/
        pscrl = scrl;                   /* save old scrl value */

        DB_CMNT("sc_adv - edge uslice");

        maskpx = nbmasks[soffset];      /* setup source pixel mask */
        masksl = ~maskpx;               /* setup target pixel mask */

        uslice(prvsl, maskpx, masksl, gdstbp);          /* update left edge */

        uslice(nxtsl, maskpx, masksl, gdstbn);          /* update right edge */

        scrl  = 0x8000 | ((soffset >> 1) ^ 0x0001);

        /* only update VSDD registers if score is up and scrl changed */

        if ((ndisp EQ 2) AND (scrl NE pscrl)) {

                sword = (uint16_t)((int32_t)saddr >> 1);

                setipl(VID_DI);         /* disable video interrupts */

                vi_scrl = scrl;
                vi_sadr = sword;

                setipl(VID_EI);         /* enable video interrupts */
        }

        ctrsw = FALSE;

#ifdef TRACEIT
        if (tracesw & 0x0002) {

                SCslice();
        }
#endif

        DB_EXIT("sc_adv");
}

/* 

*/

/*
   =============================================================================
        scupd() -- update the center slice without scrolling
   =============================================================================
*/

void scupd(void)
{
        register int16_t masksl, maskpx, i;
        register uint16_t sword;
        register int32_t tl;
        register uint16_t *optr, *qptr, *fsl;
        int16_t soff;

        DB_ENTR("scupd");

        if (v_regs[5] & 0x0180)                 /* make sure we're in bank 0 */
                vbank(0);

        soff   = (nbmoff + soffset) & 3;        /* calculate offset to use */
        maskpx = nbmasks[(2 + soff) & 3];       /* setup source pixel mask */
        masksl = ~maskpx;                       /* setup target pixel mask */
        tl = 128L;                              /* setup VSDD line increment */

        /* update VRAM, if it's time */

        if (cslice(cursl, maskpx, masksl, gdstbc) AND (ndisp EQ 2)) {

                DB_CMNT("scupd - center write ...");

                fsl  = cursl;
                optr = saddr + ((soff > 1) ? 64L : 63L);
                qptr = consl;

                for (i = 224; i--; ) {

                        if (sword = maskpx & *fsl)
                                *optr = (*optr & masksl) | sword;

                        *fsl++ = *qptr++;       /* clean up the slice */
                        optr += tl;
                }

                DB_CMNT("scupd - center written");
        }

        ctrsw = FALSE;
}