hostmot2 decode process question

StepGenDecodeProcess : process (A,readstb,writestb,StepGenRateSel, StepGenAccumSel, StepGenModeSel,
                                 			StepGenDSUTimeSel, StepGenDHLDTimeSel, StepGenPulseATimeSel, 
			                                 StepGenPulseITimeSel, StepGenTableSel, StepGenTableMaxSel)
		begin
			if A(15 downto 8) = StepGenRateAddr then	 --  stepgen rate register select
				StepGenRateSel <= '1';
			else
				StepGenRateSel <= '0';
			end if;
			if A(15 downto 8) = StepGenAccumAddr then	 --  stepgen Accumumlator low select
				StepGenAccumSel <= '1';
			else
				StepGenAccumSel <= '0';
			end if;
			if A(15 downto 8) = StepGenModeAddr then	 --  stepgen mode register select
				StepGenModeSel <= '1';
			else
				StepGenModeSel <= '0';
			end if;
			if A(15 downto 8) = StepGenDSUTimeAddr then	 --  stepgen Dir setup time register select
				StepGenDSUTimeSel <= '1';
			else
				StepGenDSUTimeSel <= '0';
			end if;
			if A(15 downto 8) =StepGenDHLDTimeAddr then	 --  stepgen Dir hold time register select
				StepGenDHLDTimeSel <= '1';
			else
				StepGenDHLDTimeSel <= '0';
			end if;
			if A(15 downto 8) = StepGenPulseATimeAddr then	 --  stepgen pulse width register select
				StepGenPulseATimeSel <= '1';
			else
				StepGenPulseATimeSel <= '0';
			end if;
			if A(15 downto 8) = StepGenPulseITimeAddr then	 --  stepgen pulse width register select
				StepGenPulseITimeSel <= '1';
			else
				StepGenPulseITimeSel <= '0';
			end if;
			if A(15 downto 8) = StepGenTableAddr then	 --  stepgen pulse width register select
				StepGenTableSel <= '1';
			else
				StepGenTableSel <= '0';
			end if;
			if A(15 downto 8) = StepGenTableMaxAddr then	 --  stepgen pulse width register select
				StepGenTableMaxSel <= '1';
			else
				StepGenTableMaxSel <= '0';
			end if;
			if A(15 downto 8) = StepGenBasicRateAddr and writestb = '1' then	 --  
				LoadStepGenBasicRate <= '1';
			else
				LoadStepGenBasicRate <= '0';
			end if;
			if A(15 downto 8) = StepGenBasicRateAddr and readstb = '1' then	 --  
				ReadStepGenBasicRate <= '1';
			else
				ReadStepGenBasicRate <= '0';
			end if;			
			LoadStepGenRate <= OneOfNDecode(STEPGENs,StepGenRateSel,writestb,A(7 downto 2)); 	-- 64 max
			ReadStepGenRate <= OneOfNDecode(STEPGENs,StepGenRateSel,readstb,A(7 downto 2)); 		-- Note: all the reads are decoded here
			LoadStepGenAccum <= OneOfNDecode(STEPGENs,StepGenAccumSel,writestb,A(7 downto 2));	-- but most are commented out in the 
			ReadStepGenAccum <= OneOfNDecode(STEPGENs,StepGenAccumSel,readstb,A(7 downto 2));	-- stepgen module hardware for space reasons
			LoadStepGenMode <= OneOfNDecode(STEPGENs,StepGenModeSel,writestb,A(7 downto 2));			 
			ReadStepGenMode <= OneOfNDecode(STEPGENs,StepGenModeSel,Readstb,A(7 downto 2));	
			LoadStepGenDSUTime <= OneOfNDecode(STEPGENs,StepGenDSUTimeSel,writestb,A(7 downto 2));
			ReadStepGenDSUTime <= OneOfNDecode(STEPGENs,StepGenDSUTimeSel,Readstb,A(7 downto 2));
			LoadStepGenDHLDTime <= OneOfNDecode(STEPGENs,StepGenDHLDTimeSel,writestb,A(7 downto 2));
			ReadStepGenDHLDTime <= OneOfNDecode(STEPGENs,StepGenDHLDTimeSel,Readstb,A(7 downto 2));
			LoadStepGenPulseATime <= OneOfNDecode(STEPGENs,StepGenPulseATimeSel,writestb,A(7 downto 2));
			ReadStepGenPulseATime <= OneOfNDecode(STEPGENs,StepGenPulseATimeSel,Readstb,A(7 downto 2));
			LoadStepGenPulseITime <= OneOfNDecode(STEPGENs,StepGenPulseITimeSel,writestb,A(7 downto 2));
			ReadStepGenPulseITime <= OneOfNDecode(STEPGENs,StepGenPulseITimeSel,Readstb,A(7 downto 2));
			LoadStepGenTable <= OneOfNDecode(STEPGENs,StepGenTableSel,writestb,A(7 downto 2));
			ReadStepGenTable <= OneOfNDecode(STEPGENs,StepGenTableSel,Readstb,A(7 downto 2));
			LoadStepGenTableMax <= OneOfNDecode(STEPGENs,StepGenTableMaxSel,writestb,A(7 downto 2));
			ReadStepGenTableMax <= OneOfNDecode(STEPGENs,StepGenTableMaxSel,Readstb,A(7 downto 2));
		end process StepGenDecodeProcess;