A. Ruiz, José

Litochevski, Moti

Lightweight 8080 compatible core

I think your ccdiv function in c80_lib is not correct?the example is following?

int tstary[2] = {0xaabb, 0x99aa};

// sends a hexadecimal value to the UART 
printhex(hval)	
int hval;
{	
	char hbyte;
	char lbyte;
	char temp;
	hbyte = hval/256; //use the >>8 is ok
	lbyte = hval%256; //
	
	sendbyte(hbyte);
	sendbyte(lbyte);
	
	temp = (hbyte & 0xf0)>>4;
	if(temp > 9)
		sendbyte('a'+temp-10);
	else
	 	sendbyte('0'+temp);	
	 	
	temp = (hbyte & 0x0f);
	if(temp > 9)
		sendbyte('a'+temp-10);
	else
	 	sendbyte('0'+temp);	
	 	
	temp = (lbyte & 0xf0)>>4;
	if(temp > 9)
		sendbyte('a'+temp-10);
	else
	 	sendbyte('0'+temp);
	
	temp = (lbyte & 0x0f);
	if(temp > 9)
		sendbyte('a'+temp-10);
	else
	 	sendbyte('0'+temp); 		
}


printstr("Hex value: 0x"); printhex(tstary[0]); nl();
printstr("Hex value: 0x"); printhex(tstary[1]); nl();


the result of print as following?

# received byte 0x30 ("0") at              1956000 ns
# received byte 0x78 ("x") at              2053000 ns
# received byte 0xab ("«") at              2270000 ns
# received byte 0xbb ("»") at              2366000 ns
# received byte 0x61 ("a") at              2461000 ns
# received byte 0x62 ("b") at              2559000 ns
# received byte 0x62 ("b") at              2654000 ns
# received byte 0x62 ("b") at              2752000 ns

# received byte 0x30 ("0") at              4112000 ns
# received byte 0x78 ("x") at              4210000 ns
# received byte 0x9a ("?") at              4427000 ns
# received byte 0xaa ("ª") at              4522000 ns
# received byte 0x39 ("9") at              4620000 ns
# received byte 0x61 ("a") at              4717000 ns
# received byte 0x61 ("a") at              4813000 ns
# received byte 0x61 ("a") at              4911000 ns

c80_lib

i think the small c comiler have a bug as follow:

int txbyte = 0x2345; //define a global variable and have a initial value

but the comliler change the c code to asm code as follow:

0481 :                  __txbyte:
0481 : 0045             	db 0,69

but if you use the matrix,the result is right:
int tstary[2] = {0x1234, 0x5678};

the compiler result is :
047d :                  __tstary:
047d : 34127856         	db 52,18,120,86

the small c compiler

hello?I am studying your 8080 cpu code?can you tell me how to software simulate the c/asm code?can you give me some example?thanks!!!!

simulate

hello! your project is very good ! can you also give some interrupt C example to test interrupt!

interrupt

Some instances of INR M worked while others did not. 

Microcode flag #setacy was missing in the microcode source for INR M (line 370 of light8080.m80) and the auxiliary carry flag used in all increments (including PC) was not being set and kept its previous value. It passed the test bench by chance, apparently.

The code in the CVS has the bug fixed.

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Lightweight 8080 compatible core