MAME SVN History

199869 Revisions

r31157 Tuesday 1st July, 2014 at 19:30:52 UTC by Alex Jackson
m6502: remove expensive and unused attotime precalculation at start of each timeslice [Alex Jackson] (nw) This precalculation seems to be part of OG's "CPU core template", as all CPU cores written by him do it. It's used to optimize things like onboard serial ports and high-frequency timers; however, the m6502 and its derivatives have neither onboard serial ports nor high-frequency timers, and the precalculation is simply a boat anchor on drivers with 6502-family CPUs and tight interleaving. mess c64 benchmarks (3.4 GHz Sandy Bridge i5; 64-bit Linux GCC 4.8 build) before: [awj@localhost trunk]$ ./mess64 -window -bench 60 c64 Average speed: 238.17% (59 seconds) [awj@localhost trunk]$ ./mess64 -window -bench 60 c64 Average speed: 236.36% (59 seconds) after: [awj@localhost trunk]$ ./mess64 -window -bench 60 c64 Average speed: 279.93% (59 seconds) [awj@localhost trunk]$ ./mess64 -window -bench 60 c64 Average speed: 279.30% (59 seconds)

r31157 Tuesday 1st July, 2014 at 19:30:52 UTC by Alex Jackson

m6502: remove expensive and unused attotime precalculation at start of each timeslice [Alex Jackson]

(nw)
This precalculation seems to be part of OG's "CPU core template", as all CPU
cores written by him do it. It's used to optimize things like onboard serial
ports and high-frequency timers; however, the m6502 and its derivatives have
neither onboard serial ports nor high-frequency timers, and the precalculation
is simply a boat anchor on drivers with 6502-family CPUs and tight interleaving.

mess c64 benchmarks (3.4 GHz Sandy Bridge i5; 64-bit Linux GCC 4.8 build)

before:
[awj@localhost trunk]$ ./mess64 -window -bench 60 c64
Average speed: 238.17% (59 seconds)
[awj@localhost trunk]$ ./mess64 -window -bench 60 c64
Average speed: 236.36% (59 seconds)

after:
[awj@localhost trunk]$ ./mess64 -window -bench 60 c64
Average speed: 279.93% (59 seconds)
[awj@localhost trunk]$ ./mess64 -window -bench 60 c64
Average speed: 279.30% (59 seconds)

[src/emu/cpu/m6502]

m6502.c m6502.h m740.c

trunk/src/emu/cpu/m6502/m6502.c
r31156	r31157
129	129	inst_substate = 0;
130	130	inst_state_base = 0;
131	131	sync = false;
132		end_cycles = 0;
133	132	inhibit_interrupts = false;
134	133	}
135	134
r31156	r31157
143	142	apu_irq_state = false;
144	143	irq_taken = false;
145	144	v_state = false;
146		end_cycles = 0;
147	145	sync = false;
148	146	sync_w(CLEAR_LINE);
149	147	inhibit_interrupts = false;
r31156	r31157
400	398	return v;
401	399	}
402	400
403		UINT64 m6502_device::get_cycle()
404		{
405		return end_cycles == 0 \|\| icount <= 0 ? machine().time().as_ticks(clock()) : end_cycles - icount;
406		}
407
408	401	void m6502_device::execute_run()
409	402	{
410		end_cycles = machine().time().as_ticks(clock()) + icount;
411	403	if(inst_substate)
412	404	do_exec_partial();
413	405
r31156	r31157
420	412	}
421	413	do_exec_full();
422	414	}
423		end_cycles = 0;
424	415	}
425	416
426	417	void m6502_device::execute_set_input(int inputnum, int state)

trunk/src/emu/cpu/m6502/m6502.h
r31156	r31157
61	61	DECLARE_WRITE_LINE_MEMBER( irq_line );
62	62	DECLARE_WRITE_LINE_MEMBER( nmi_line );
63	63
64		UINT64 get_cycle();
65	64	bool get_sync() const { return sync; }
66	65	void disable_direct() { direct_disabled = true; }
67	66
r31156	r31157
201	200	int icount;
202	201	bool nmi_state, irq_state, apu_irq_state, v_state;
203	202	bool irq_taken, sync, direct_disabled, inhibit_interrupts;
204		UINT64 end_cycles;
205	203
206	204	static const disasm_entry disasm_entries[0x100];
207	205

trunk/src/emu/cpu/m6502/m740.c
r31156	r31157
77	77	apu_irq_state = false;
78	78	irq_taken = false;
79	79	v_state = false;
80		end_cycles = 0;
81	80	sync = false;
82	81	inhibit_interrupts = false;
83	82	SP = 0x00ff;

199869 Revisions