GP32 demo code (offscr)

@sang

Published in 

GP32

 · 4 Mar 2024

This simple demo demonstrates vertical scrolling using virtual screens and changing frame buffer pointers.

This demo bangs the hardware bypassing the BIOS (tested with 157e FW).

offscr.c

// (c) 13-Jul-2002 Jouni 'Mr.Spiv' Korhonen 
// 

#include "gpdef.h" 
#include "gpstdlib.h" 
#include "gpgraphic.h" 
#include "gpmain.h" 
#include "gpfont.h" 

#include <stdlib.h> 
#include <string.h> 

// strcoll, ptrdiff_t, memcmp, strspn strerror 

GPDRAWSURFACE gpDraw; 
GPDRAWTAG gpDrawTag; 

volatile long* tpal = (long*)0x14a00050; 
volatile long* lcdcon1 = (long*)0x14a00000; 
volatile long* lcdcon2 = (long*)0x14a00004; 
volatile long* lcdcon3 = (long*)0x14a00008; 
volatile long* lcdcon4 = (long*)0x14a0000c; 
volatile long* lcdcon5 = (long*)0x14a00010; 

volatile long* lcdaddr1 = (long*)0x14a00014; 
volatile long* lcdaddr2 = (long*)0x14a00018; 
volatile long* lcdaddr3 = (long*)0x14a0001c; 

 
volatile long* hwpal = (long*)0x14a00400; 

extern unsigned char BK_Pic_c[]; 

// 
// 
// 

void waitline( int line ) { 
	while (line != ((*lcdcon1 >> 18) & 0x1ff) ); 
} 

 
// 
// 
// 
// 
// 

void GpMain(void *arg) 
{ 
	long scrptru; 
	long scrptrl, scrptrl2; 
	long ptr; 
	char buf[100]; 
	int m,n; 

	unsigned short *dst; 
	unsigned short *src; 

 
	volatile unsigned long *gpb = (unsigned long *)0x1560000c; 
	volatile unsigned long *gpe = (unsigned long *)0x15600030; 

	// 

	//GpGraphicModeSet(GPC_DFLAG_16BPP,NULL); 
	//*lcdcon5 |= 1; 
	//GpLcdSurfaceGet(&gpDraw, 0); 
	//GpRectFill(NULL, &gpDraw, 0, 0, gpDraw.buf_w, gpDraw.buf_h, 0x01); 

	// 
	//dst = (unsigned short*)gpDraw.ptbuffer; 
	dst = (unsigned short*)0x0C7B4000; 
	src = (unsigned short*)BK_Pic_c; 

	for (m = 0; m < 320; m++) { 
		for (n = 0; n < 240; n++) { 
			*dst++ = *src++; 
		} 
		for (n = 0; n < 240; n++) { 
			*dst = dst[-240]; 
			dst++; 
		} 
	} 

 
	//gm_sprintf(buf,"src: %08x, dst: %08x",src,dst); 
	//GpTextOut(NULL,&gpDraw,10,120,buf,0xaa); 

 
    //GpSurfaceSet(&gpDraw);  //gpDraw primary surface· setting 

	// 320x240x16 screen mode, 0 pixel offscreen 
	// expects 33MHz HCLK 
#if 1 
	*lcdcon1 = ((3 << 8) | (0 << 7) | (3 << 5) | (12 << 1) | (0)); 
							// CLKVAL=3, VNMODE=0, PNRMODE=TFT, BPPMODE=1100 (16bits), ENDID=0 
	*lcdcon2 = ((1 << 24) | (319 << 14) | (2 << 6) | 1); 
							// VBPD=1, LINEVAL=319, VFPD=2, VSPW=1 
	*lcdcon3 = ((6 << 19) | (239 << 8) | (2)); 
							// HBPD=6, HOZVAL=239, HFPD=2 
	*lcdcon4 = ((0 << 24) | (0 << 16) | (4)); 
							// PALADDEN=0, ADDVAL=0, HSPW=4 
	*lcdcon5 = ((1 << 10) | (1 << 9) | (1 << 8) | (0 << 7) | (0 << 6) | (0 << 4) | (0 << 2) | (1)); 
							// INVVCLK=1, INVVLINE=1, INVVFRAME=1, INVVD=0, INVVDEN=0 
							// INVENDLINE=0, ENLEND=0, BSWP=0, HWSWP=1 
	*tpal = 0; 

	ptr =         (long)0x0C7B4000; 
	*lcdaddr1 = ((ptr & 0x0fc00000) >> 1) | ((ptr & 0x3ffffe) >> 1); 
	*lcdaddr2 = ((ptr & 0x003ffffe) >> 1) + (240+240) * (319+1); 

	*lcdaddr3 = ((240 << 11) | (240)); 
							// OFFSIZE=0, PAGEWIDTH=240 halfwords -> 240 pixels 

	*lcdcon1 |= 1;	// enable lcd 
#endif 

 
	// 
	scrptru = *lcdaddr1; 
	//scrptrl = *lcdaddr2; 
	//scrptrl = *lcdaddr2 - 240; 
	//scrptrl = *lcdaddr2 - 240*2; 
	scrptrl = *lcdaddr2; 

	n = 0; 
	m = 0; 

	while ((GpKeyGet() & (GPC_VK_FL | GPC_VK_FR)) != (GPC_VK_FL | GPC_VK_FR)) { 
		long reg, reg2; 

		waitline(2); 

		if (n++ == 240) { 
			*lcdaddr1 = scrptru; 
			*lcdaddr2 = scrptrl; 
			n = 0; 
		} else { 
			*lcdaddr1 += 1; 
			*lcdaddr2 += 1; 
		} 

		waitline(1); 

 
	} 

 
	*tpal = 0x0001ffff; 
	// reboot.. 

	while ((GpKeyGet() & (GPC_VK_SELECT | GPC_VK_START)) != (GPC_VK_SELECT | GPC_VK_START)); 
	GpAppExit(); 
}