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8bitworkshop/presets/nes/vrambuf.h
2019-07-16 09:55:41 -04:00

44 lines
1.0 KiB
C

#ifndef _VRAMBUF_H
#define _VRAMBUF_H
#include "neslib.h"
// VBUFSIZE = maximum update buffer bytes
#define VBUFSIZE 128
// update buffer starts at $100 (stack page)
#define updbuf ((byte*)0x100)
// index to end of buffer
extern byte updptr;
// C versions of macros
#define VRAMBUF_SET(b) updbuf[updptr] = (b);
#define VRAMBUF_ADD(b) VRAMBUF_SET(b); ++updptr
// macro to add a raw header (useful for single bytes)
#define VRAMBUF_PUT(addr,len,flags)\
VRAMBUF_ADD(((addr) >> 8) | (flags));\
VRAMBUF_ADD(addr);\
VRAMBUF_ADD(len);
// OR with address to put vertical run
#define VRAMBUF_VERT 0x8000
// add EOF marker to buffer (but don't increment pointer)
void vrambuf_end(void);
// clear vram buffer and place EOF marker
void vrambuf_clear(void);
// wait for next frame, then clear buffer
// this assumes the NMI will call flush_vram_update()
void vrambuf_flush(void);
// add multiple characters to update buffer
// using horizontal increment
void vrambuf_put(word addr, const char* str, byte len);
#endif // vrambuf.h