mirror of
https://github.com/sehugg/8bitworkshop.git
synced 2024-11-29 14:51:17 +00:00
151 lines
3.4 KiB
C
151 lines
3.4 KiB
C
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#include "dll.h"
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#include <string.h>
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DLLEntry DLL[NUMSLOTS]; // display list list
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byte DL[NUMSLOTS][SLOTSIZE]; // display list slots
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byte DL_len[NUMSLOTS]; // current bytes in each slot
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#ifdef DLSAVE
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byte DL_save[NUMSLOTS]; // save lengths of each slot
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#endif
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byte slot0 = 0; // current page offset
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// set display list list address registers
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void dll_set_addr(const void* dpp) {
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MARIA.DPPH = (word)dpp>>8;
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MARIA.DPPL = (byte)dpp;
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}
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// clear the current page
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void dll_clear() {
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byte i;
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for (i=slot0; i<slot0+SLOTSPERPAGE; i++) {
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DL_len[i] = 0;
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DL[i][1] = 0;
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}
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}
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#ifdef DLSAVE
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// save display list lengths of each slot
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void dll_save() {
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memcpy(DL_save, DL_len, sizeof(DL_save));
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}
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// restore display list lengths of current page
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void dll_restore() {
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byte i;
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for (i=slot0; i<slot0+SLOTSPERPAGE; i++) {
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DL_len[i] = DL_save[i]; // set slot length
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DL[i][DL_len[i]+1] = 0; // set end marker
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}
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}
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// restore all slots
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void dll_restore_all() {
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slot0 ^= SLOTSPERPAGE;
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dll_restore();
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slot0 ^= SLOTSPERPAGE;
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dll_restore();
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}
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#endif
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#ifdef DOUBLEBUFFER
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// swap between pages
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void dll_swap() {
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slot0 ^= SLOTSPERPAGE;
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if (!slot0) {
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dll_set_addr(DLL+SLOTSPERPAGE);
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} else {
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dll_set_addr(DLL);
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}
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}
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// copy offscreen page to current page
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void dll_copy() {
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memcpy(&DL[slot0], &DL[slot0 ^ SLOTSPERPAGE], SLOTSIZE*SLOTSPERPAGE);
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memcpy(&DL_len[slot0], &DL_len[slot0 ^ SLOTSPERPAGE], SLOTSPERPAGE);
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}
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#endif
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// set scroll position
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void dll_set_scroll(byte y) {
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static byte oldslot = 0;
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byte slot = y / SLOTHEIGHT;
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byte offset = 15 - (y & 15);
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DLL[oldslot].offset_flags = DLL_FLAGS | (SLOTHEIGHT-1);
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DLL[slot].offset_flags = DLL_FLAGS | offset;
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dll_set_addr(DLL + slot);
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oldslot = slot;
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}
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// allocate a given # of bytes in a slot
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sbyte dll_bytesleft(byte slot) {
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slot &= NUMSLOTS-1;
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return SLOTSIZE - DL_len[slot];
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}
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// allocate a given # of bytes in a slot
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void* dll_alloc(byte slot, byte len) {
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byte dlofs;
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register byte* dl;
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slot &= NUMSLOTS-1;
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dl = DL[slot];
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dlofs = DL_len[slot];
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DL_len[slot] += len;
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dl[dlofs+len+1] = 0;
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return &dl[dlofs];
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}
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// add a sprite to currently selected page
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void dll_add_sprite(word addr, byte x, byte y, byte wpal) {
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byte slot = (y / SLOTHEIGHT) | slot0;
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register DL4Entry* dl = (DL4Entry*) dll_alloc(slot, 4);
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dl->data_lo = (byte)addr;
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dl->data_hi = (byte)(addr>>8) + (y & 15);
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dl->xpos = x;
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dl->width_pal = wpal;
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if (y & 15) {
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DL4Entry* dl2 = (DL4Entry*) dll_alloc(slot+1, 4);
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*dl2 = *dl;
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dl2->data_hi -= SLOTHEIGHT;
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}
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}
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// add a string to currently selected page
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// strings are aligned to top of slot
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void dll_add_string(register const char* str, byte x, byte y, byte wpal) {
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byte slot = (y / SLOTHEIGHT) | slot0;
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register DL5Entry* dl = (DL5Entry*) dll_alloc(slot, 5);
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dl->data_lo = (byte)str;
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dl->data_hi = (word)str>>8;
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dl->flags = DL5_INDIRECT;
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dl->width_pal = wpal;
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dl->xpos = x;
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}
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// set up display lists
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void dll_setup() {
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byte i;
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byte* dlptr = &DL[0][0];
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register DLLEntry *dll = &DLL[0];
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for (i=0; i<NUMSLOTS; i++) {
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dll->offset_flags = DLL_FLAGS | (SLOTHEIGHT-1);
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dll->dl_hi = (word)dlptr>>8;
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dll->dl_lo = (byte)dlptr;
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dlptr += sizeof(DL[0]);
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dll++;
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}
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dll_clear();
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#ifdef DOUBLEBUFFER
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dll_swap();
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dll_clear();
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dll_swap();
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#else
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dll_set_addr(DLL);
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#endif
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#ifdef DLSAVE
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memset(DL_save, 0, sizeof(DL_save));
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#endif
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}
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