m6809b.abl

自己编写的GAL可编程逻辑电路的编译软件abel4的windows界面

module M6809B
title '6809 memory decode
Jean Designer  Data I/O Corp Redmond WA   5 Aug 1990'

	m6809			device	'P14L4';
	A15,A14,A13,A12,A11,A10	pin 1,2,3,4,5,6;
	ROM1,IO,ROM2,DRAM	pin 14,15,16,17;

	H,L,X	= 1,0,.X.;
	Address	= [A15,A14,A13,A12, A11,A10,X,X, X,X,X,X, X,X,X,X];

" This macro will return an 'L' if the address (a) is between the
" two limits (b,c), otherwise it returns an 'H'.
between macro (a,b,c)
	{@if ((?a>=?b)&(?a<=?c)){L}@if!((?a>=?b)&(?a<=?c)){H}};

equations
	!DRAM	= (Address <= ^hDFFF);

	!IO	= (Address >= ^hE000) & (Address <= ^hE7FF);

	!ROM2   = (Address >= ^hF000) & (Address <= ^hF7FF);

	!ROM1	= (Address >= ^hF800);

test_vectors (Address -> [DRAM, IO, ROM2, ROM1])
	@IRP addrs (^h0000,^h8000,^hE100,^hE800,^hF100,^hFC00) {

		?addrs  -> [ between (?addrs,^h0000,^hDFFF),	" DRAM
		             between (?addrs,^hE000,^hE7FF),	" IO
		             between (?addrs,^hF000,^hF7FF),	" ROM2
		             between (?addrs,^hF800,^hFFFF)];	" ROM1}
end