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r26264 Monday 18th November, 2013 at 16:11:49 UTC by Jürgen Buchmüller
Fix the alu_74181 function. Now using ALU.a10 as lookup for accuracy.

[/branches/alto2/src/emu/cpu/alto2]

alto2.c alto2.h

branches/alto2/src/emu/cpu/alto2/alto2.c

r26263	r26264
2346	2346	* </PRE>
2347	2347	*/
2348	2348
	2349	enum {
	2350	A10_UNUSED  = (1 << 0),
	2351	A10_TSELECT = (1 << 1),
	2352	A10_ALUCI   = (1 << 2),
	2353	A10_ALUM    = (1 << 3),
	2354	A10_ALUS0   = (1 << 4),
	2355	A10_ALUS1   = (1 << 5),
	2356	A10_ALUS2   = (1 << 6),
	2357	A10_ALUS3   = (1 << 7),
	2358	A10_ALUIN   = (A10_ALUM|A10_ALUCI|A10_ALUS0|A10_ALUS1|A10_ALUS2|A10_ALUS3)
	2359	};
	2360
2349	2361	//! S function, M flag and C carry in
2350		#define   SMC(s3,s2,s1,s0,m,c) (((s3)<<7)|((s2)<<6)|((s1)<<5)|((s0)<<4)|((m)<<3)|((c)<<2))
	2362	#define   SMC(s3,s2,s1,s0,m,ci) (s3*A10_ALUS3 + s2*A10_ALUS2 + s1*A10_ALUS1 + s0*A10_ALUS0 + m*A10_ALUM + ci*A10_ALUCI)
2351	2363
2352	2364	/**
2353		* @brief Compute the 74181 ALU operation smc
	2365	* @brief Compute the 74181 ALU operation smc for inputs a and b
	2366	*
	2367	* The function, arithmetic / logic flag and carry in define the
	2368	* ALU operation. The carry in is irrelevant for the logic operations.
	2369	* The result is 17 bit, where bit #16 is the carry out.
	2370	*
2354	2371	* @param smc S function [0-15], M arithmetic/logic flag, C carry
2355	2372	* @return resulting ALU output
2356	2373	*/
2357		UINT32 alto2_cpu_device::alu_74181(UINT32 smc)
	2374	UINT32 alto2_cpu_device::alu_74181(UINT32 a, UINT32 b, UINT8 smc)
2358	2375	{
2359		register UINT32 a = m_bus;
2360		register UINT32 b = m_t;
2361		register UINT32 s = 0;
2362		register UINT32 f = 0;
	2376	register UINT32 f;
	2377	register const UINT32 cout = 1 << 16;
2363	2378
2364		switch (smc & SMC(1,1,1,1, 1, 1)) {
	2379	switch (smc & A10_ALUIN) {
2365	2380	case SMC(0,0,0,0, 0, 0): // 0000: A + 1
2366	2381	f = a + 1;
2367	2382	break;
r26263	r26264
2370	2385	f = a;
2371	2386	break;
2372	2387
	2388	case SMC(0,0,0,0, 1, 0): // 0000: A'
	2389	case SMC(0,0,0,0, 1, 1):
	2390	f = (~a) | cout;
	2391	break;
	2392
2373	2393	case SMC(0,0,0,1, 0, 0): // 0001: (A | B) + 1
2374	2394	f = (a | b) + 1;
2375	2395	break;
r26263	r26264
2378	2398	f = a | b;
2379	2399	break;
2380	2400
	2401	case SMC(0,0,0,1, 1, 0): // 0001: A' | B'
	2402	case SMC(0,0,0,1, 1, 1):
	2403	f = (~a | ~b) | cout;
	2404	break;
	2405
2381	2406	case SMC(0,0,1,0, 0, 0): // 0010: (A | B') + 1
2382	2407	f = (a | ~b) + 1;
2383	2408	break;
r26263	r26264
2386	2411	f = a | ~b;
2387	2412	break;
2388	2413
	2414	case SMC(0,0,1,0, 1, 0): // 0010: A' & B
	2415	case SMC(0,0,1,0, 1, 1):
	2416	f = (~a & b) | cout;
	2417	break;
	2418
2389	2419	case SMC(0,0,1,1, 0, 0): // 0011: -1 + 1
2390		s = 1;
2391		f = -1 + 1;
	2420	f = (-1 + 1) | cout;
2392	2421	break;
2393	2422
2394	2423	case SMC(0,0,1,1, 0, 1): // 0011: -1
2395		s = 1;
2396		f = -1;
	2424	f = (-1) | cout;
2397	2425	break;
2398	2426
	2427	case SMC(0,0,1,1, 1, 0): // 0011: logic 0
	2428	case SMC(0,0,1,1, 1, 1):
	2429	f = cout;
	2430	break;
	2431
2399	2432	case SMC(0,1,0,0, 0, 0): // 0100: A + (A & B') + 1
2400	2433	f = a + (a & ~b) + 1;
2401	2434	break;
r26263	r26264
2404	2437	f = a + (a & ~b);
2405	2438	break;
2406	2439
	2440	case SMC(0,1,0,0, 1, 0): // 0100: (A & B)'
	2441	case SMC(0,1,0,0, 1, 1):
	2442	f = ~(a & b) | cout;
	2443	break;
	2444
2407	2445	case SMC(0,1,0,1, 0, 0): // 0101: (A | B) + (A & B') + 1
2408	2446	f = (a | b) + (a & ~b) + 1;
2409	2447	break;
r26263	r26264
2412	2450	f = (a | b) + (a & ~b);
2413	2451	break;
2414	2452
	2453	case SMC(0,1,0,1, 1, 0): // 0101: B'
	2454	case SMC(0,1,0,1, 1, 1):
	2455	f = (~b) | cout;
	2456	break;
	2457
2415	2458	case SMC(0,1,1,0, 0, 0): // 0110: A - B - 1 + 1
2416		s = 1;
2417		f = a - b - 1 + 1;
	2459	f = (a - b - 1 + 1)  ^ cout;
2418	2460	break;
2419	2461
2420	2462	case SMC(0,1,1,0, 0, 1): // 0110: A - B - 1
2421		s = 1;
2422		f = a - b - 1;
	2463	f = (a - b - 1) ^ cout;
2423	2464	break;
2424	2465
	2466	case SMC(0,1,1,0, 1, 0): // 0110: A ^ B
	2467	case SMC(0,1,1,0, 1, 1):
	2468	f = (a ^ b) | cout;
	2469	break;
	2470
2425	2471	case SMC(0,1,1,1, 0, 0): // 0111: (A & B) - 1 + 1
2426		s = 1;
2427		f = (a & b) - 1 + 1;
	2472	f = ((a & b) - 1 + 1) ^ cout;
2428	2473	break;
2429	2474
2430	2475	case SMC(0,1,1,1, 0, 1): // 0111: (A & B) - 1
2431		s = 1;
2432		f = (a & b) - 1;
	2476	f = ((a & b) - 1) ^ cout;
2433	2477	break;
2434	2478
	2479	case SMC(0,1,1,1, 1, 0): // 0111: A & B'
	2480	case SMC(0,1,1,1, 1, 1):
	2481	f = (a & ~b) | cout;
	2482	break;
	2483
2435	2484	case SMC(1,0,0,0, 0, 0): // 1000: A + (A & B) + 1
2436	2485	f = a + (a & b) + 1;
2437	2486	break;
r26263	r26264
2440	2489	f = a + (a & b);
2441	2490	break;
2442	2491
	2492	case SMC(1,0,0,0, 1, 0): // 1000: A' | B
	2493	case SMC(1,0,0,0, 1, 1):
	2494	f = (~a | b) | cout;
	2495	break;
	2496
2443	2497	case SMC(1,0,0,1, 0, 0): // 1001: A + B + 1
2444	2498	f = a + b + 1;
2445	2499	break;
r26263	r26264
2448	2502	f = a + b;
2449	2503	break;
2450	2504
	2505	case SMC(1,0,0,1, 1, 0): // 1001: A' ^ B'
	2506	case SMC(1,0,0,1, 1, 1):
	2507	f = (~a ^ ~b) | cout;
	2508	break;
	2509
2451	2510	case SMC(1,0,1,0, 0, 0): // 1010: (A | B') + (A & B) + 1
2452	2511	f = (a | ~b) + (a & b) + 1;
2453	2512	break;
r26263	r26264
2456	2515	f = (a | ~b) + (a & b);
2457	2516	break;
2458	2517
	2518	case SMC(1,0,1,0, 1, 0): // 1010: B
	2519	case SMC(1,0,1,0, 1, 1):
	2520	f = (b) | cout;
	2521	break;
	2522
2459	2523	case SMC(1,0,1,1, 0, 0): // 1011: (A & B) - 1 + 1
2460		s = 1;
2461		f = (a & b) - 1 + 1;
	2524	f = ((a & b) - 1 + 1) ^ cout;
2462	2525	break;
2463	2526
2464	2527	case SMC(1,0,1,1, 0, 1): // 1011: (A & B) - 1
2465		s = 1;
2466		f = (a & b) - 1;
	2528	f = ((a & b) - 1)  ^ cout;
2467	2529	break;
2468	2530
	2531	case SMC(1,0,1,1, 1, 0): // 1011: A & B
	2532	case SMC(1,0,1,1, 1, 1):
	2533	f = (a & b) | cout;
	2534	break;
	2535
2469	2536	case SMC(1,1,0,0, 0, 0): // 1100: A + A + 1
2470	2537	f = a + a + 1;
2471	2538	break;
r26263	r26264
2474	2541	f = a + a;
2475	2542	break;
2476	2543
	2544	case SMC(1,1,0,0, 1, 0): // 1100: logic 1
	2545	case SMC(1,1,0,0, 1, 1):
	2546	f = (~0) | cout;
	2547	break;
	2548
2477	2549	case SMC(1,1,0,1, 0, 0): // 1101: (A | B) + A + 1
2478	2550	f = (a | b) + a + 1;
2479	2551	break;
r26263	r26264
2482	2554	f = (a | b) + a;
2483	2555	break;
2484	2556
	2557	case SMC(1,1,0,1, 1, 0): // 1101: A | B'
	2558	case SMC(1,1,0,1, 1, 1):
	2559	f = (a | ~b) | cout;
	2560	break;
	2561
2485	2562	case SMC(1,1,1,0, 0, 0): // 1110: (A | B') + A + 1
2486	2563	f = (a | ~b) + a + 1;
2487	2564	break;
r26263	r26264
2490	2567	f = (a | ~b) + a;
2491	2568	break;
2492	2569
	2570	case SMC(1,1,1,0, 1, 0): // 1110: A | B
	2571	case SMC(1,1,1,0, 1, 1):
	2572	f = (a | b) | cout;
	2573	break;
	2574
2493	2575	case SMC(1,1,1,1, 0, 0): // 1111: A - 1 + 1
2494		s = 1;
2495		f = a - 1 + 1;
	2576	f = (a - 1 + 1) ^ cout;
2496	2577	break;
2497	2578
2498	2579	case SMC(1,1,1,1, 0, 1): // 1111: A - 1
2499		s = 1;
2500		f = a - 1;
	2580	f = (a - 1) ^ cout;
2501	2581	break;
2502	2582
2503		case SMC(0,0,0,0, 1, 0): // 0000: A'
2504		case SMC(0,0,0,0, 1, 1):
2505		f = ~a;
2506		break;
2507
2508		case SMC(0,0,0,1, 1, 0): // 0001: A' | B'
2509		case SMC(0,0,0,1, 1, 1):
2510		f = ~a | ~b;
2511		break;
2512
2513		case SMC(0,0,1,0, 1, 0): // 0010: A' & B
2514		case SMC(0,0,1,0, 1, 1):
2515		f = ~a & b;
2516		break;
2517
2518		case SMC(0,0,1,1, 1, 0): // 0011: logic 0
2519		case SMC(0,0,1,1, 1, 1):
2520		f = 0;
2521		break;
2522
2523		case SMC(0,1,0,0, 1, 0): // 0100: (A & B)'
2524		case SMC(0,1,0,0, 1, 1):
2525		f = ~(a & b);
2526		break;
2527
2528		case SMC(0,1,0,1, 1, 0): // 0101: B'
2529		case SMC(0,1,0,1, 1, 1):
2530		f = ~b;
2531		break;
2532
2533		case SMC(0,1,1,0, 1, 0): // 0110: A ^ B
2534		case SMC(0,1,1,0, 1, 1):
2535		f = a ^ b;
2536		break;
2537
2538		case SMC(0,1,1,1, 1, 0): // 0111: A & B'
2539		case SMC(0,1,1,1, 1, 1):
2540		f = a & ~b;
2541		break;
2542
2543		case SMC(1,0,0,0, 1, 0): // 1000: A' | B
2544		case SMC(1,0,0,0, 1, 1):
2545		f = ~a | b;
2546		break;
2547
2548		case SMC(1,0,0,1, 1, 0): // 1001: A' ^ B'
2549		case SMC(1,0,0,1, 1, 1):
2550		f = ~a ^ ~b;
2551		break;
2552
2553		case SMC(1,0,1,0, 1, 0): // 1010: B
2554		case SMC(1,0,1,0, 1, 1):
2555		f = b;
2556		break;
2557
2558		case SMC(1,0,1,1, 1, 0): // 1011: A & B
2559		case SMC(1,0,1,1, 1, 1):
2560		f = a & b;
2561		break;
2562
2563		case SMC(1,1,0,0, 1, 0): // 1100: logic 1
2564		case SMC(1,1,0,0, 1, 1):
2565		f = ~0;
2566		break;
2567
2568		case SMC(1,1,0,1, 1, 0): // 1101: A | B'
2569		case SMC(1,1,0,1, 1, 1):
2570		f = a | ~b;
2571		break;
2572
2573		case SMC(1,1,1,0, 1, 0): // 1110: A | B
2574		case SMC(1,1,1,0, 1, 1):
2575		f = a | b;
2576		break;
2577
2578	2583	case SMC(1,1,1,1, 1, 0): // 1111: A
2579	2584	case SMC(1,1,1,1, 1, 1):
2580		f = a;
	2585	f = (a) | cout;
2581	2586	break;
2582	2587	}
2583		if (smc & 2) {
2584		m_aluc0 = ((f >> 16) ^ s) & 1;
2585		} else {
2586		m_aluc0 = 1;
2587		}
2588	2588	return f;
2589	2589	}
2590	2590	#endif
2591	2591
2592	2592	/** @brief flag that tells whether to load the T register from BUS or ALU */
2593		#define   TSELECT   (1 << 1)
	2593	#define   TSELECT   A10_TSELECT
2594	2594
2595	2595	/** @brief flag that tells wheter operation was 0: logic (M=1) or 1: arithmetic (M=0) */
2596		#define   ALUM2   (1 << 3)
	2596	#define   ALUM2   A10_ALUM
2597	2597
2598	2598	/** @brief execute the CPU for at most nsecs nano seconds */
2599	2599	void alto2_cpu_device::execute_run()
r26263	r26264
2603	2603
2604	2604	do {
2605	2605	int do_bs, flags;
2606		UINT32 alu;
2607	2606
2608	2607	/*
2609	2608	* Subtract the microcycle time from the display time accu.
r26263	r26264
2734	2733	// B4: ALUS0'   B5: ALUS1'   B6: ALUS2'   B7: ALUS3'
2735	2734	// B3-B7 are inverted on loading the PROM
2736	2735	UINT8 a10 = m_alu_a10[(m_emu.skip << 4) | aluf];
2737		alu = alu_74181(a10);
	2736	UINT32 alu = alu_74181(m_bus, m_t, a10);
	2737	m_aluc0 = (alu >> 16) & 1;
2738	2738	flags = (a10 ^ ALUM2) & (TSELECT | ALUM2);
	2739	m_alu = static_cast<UINT16>(alu);
2739	2740	#else
	2741	UINT32 alu;
2740	2742	/* compute the ALU function */
2741	2743	switch (aluf) {
2742	2744	/**
r26263	r26264
2924	2926	/**
2925	2927	* 16: ALU ← BUS
2926	2928	* PROM data for S3-0:1111 M:1 C:0 T:1
2927		* 74181 perhaps F=0 (0011/0/0)
2928		* T source is BUS
	2929	* 74181 function F=A
	2930	* T source is ALU
2929	2931	*/
2930	2932	case aluf_undef_16:
2931	2933	alu = m_bus;
r26263	r26264
2937	2939	/**
2938	2940	* 17: ALU ← BUS
2939	2941	* PROM data for S3-0:1111 M:1 C:0 T:1
2940		* 74181 perhaps F=~0 (0011/0/1)
2941		* T source is BUS
	2942	* 74181 function F=A
	2943	* T source is ALU
2942	2944	*/
2943	2945	case aluf_undef_17:
2944	2946	default:
r26263	r26264
2947	2949	flags = TSELECT;
2948	2950	LOG((LOG_CPU,0,"   ALU← 0 (illegal aluf in task %s, mpc:%05o aluf:%02o)\n", task_name(m_task), m_mpc, aluf));
2949	2951	}
	2952	m_alu = static_cast<UINT16>(alu);
2950	2953	#endif
2951		m_alu = static_cast<UINT16>(alu);
2952	2954
2953	2955	/* WRTRAM now, before L is changed */
2954	2956	if (m_wrtram_flag)

branches/alto2/src/emu/cpu/alto2/alto2.h

r26263	r26264
24	24	#endif
25	25
26	26	#define   USE_PRIO_F9318         0   //!< define to 1 to use the F9318 priority encoder code
27		#define   USE_ALU_74181         0   //!< define to 1 to use the SN74181 ALU code
	27	#define   USE_ALU_74181         1   //!< define to 1 to use the SN74181 ALU code
28	28	#define   DEBUG_DISPLAY_TIMING   0   //!< define to 1 to debug the display timing
29	29	#define   USE_BITCLK_TIMER      0   //!< define to 1 to use a very high rate timer for the disk bit clock
30	30	#define   ALTO2_HAMMING_CHECK      0   //!< define to 1 to incorporate the Hamming code and Parity check
r26263	r26264
1111	1111	void f2_load_md_1();                     //!< f2_load_md late: load memory data
1112	1112
1113	1113	UINT8* m_alu_a10;                        //!< ALU function to 74181 operation lookup PROM
1114		UINT32 alu_74181(UINT32 smc);
	1114	UINT32 alu_74181(UINT32 a, UINT32 b, UINT8 smc);
1115	1115
1116	1116	void rdram();                           //!< read the microcode ROM/RAM halfword
1117	1117	void wrtram();                           //!< write the microcode RAM from M register and ALU

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