6502/EightBit
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94 Commits

Author SHA1 Message Date
Adrian Conlon
5522fde9a7 Make the flag manipulations in the 6502 implementatin a little more comprehensible 2021-12-08 19:47:35 +00:00
Adrian Conlon
03b536838b Some constexpr improvements in low level classes. 
Signed-off-by: Adrian Conlon <adrian.conlon@gmail.com>
 2021-10-24 11:12:23 +01:00
Adrian Conlon
22506ea56c Extensive change warning: lots of "noexcept" and "constexpr" changes. Not sure if I'll keep all of them, but interesting... 
Signed-off-by: Adrian Conlon <adrian.conlon@gmail.com>
 2021-07-18 14:28:40 +01:00
Adrian Conlon
2fa9ffd1e3 Tidy up some C++ a little 
Signed-off-by: Adrian Conlon <adrian.conlon@gmail.com>
 2021-04-07 21:36:09 +01:00
Adrian Conlon
b1ca06447f Ensure 6502 uses memory rather than bus read/write mechanism 
Signed-off-by: Adrian Conlon <adrian.conlon@gmail.com>
 2021-03-08 16:44:09 +00:00
Adrian Conlon
c8bdabf34f Reflect that the I/O for Intel style processors isn't part of the CPU, but attached to the Bus and access controlled by the CPU. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2020-02-09 11:51:58 +00:00
Adrian Conlon
d0467421ff Improve compatibility with .net emulator code. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2019-11-09 18:58:23 +00:00
Adrian Conlon
ee3ecc682d Add R/W pins to the MC6809 and MOS6502 processors. Hoping it'll ease peripheral development. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2019-09-15 12:49:32 +01:00
Adrian Conlon
254cfbe342 Tidied up pin management to be synchronised with the .Net code. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2019-09-06 23:55:57 +01:00
Adrian Conlon
f0376fa81e Use macros to define our device pins. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2019-01-14 23:17:54 +00:00
Adrian Conlon
92d23d82d6 Start big refactor of device/CPU pin usage (to allow pin events throughout). 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2019-01-14 02:10:17 +00:00
Adrian Conlon
87d86bcd84 Whoops: missed unneeded method declaration. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2019-01-09 00:08:03 +00:00
Adrian Conlon
01175cf9eb Add support for emulated SYNC and RDY lines. Untested, but feel close. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2019-01-08 23:55:27 +00:00
Adrian Conlon
047babbe7c Rearrange the RESET handler for cycle accuracy. Use more of the general interrupt handler, but with "dummy" stack write access. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2019-01-08 23:09:52 +00:00
Adrian Conlon
25321e78e7 Now that HALT/RESET/NMI/IRQ and BRK have a unified architecture, I think this wraps up the instruction handler of the 6502. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2019-01-08 01:32:43 +00:00
Adrian Conlon
06e2a5c947 Start unifying 6502 interrupt handling. NMI/IRQ/BRK are all doing mostly the same work. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2019-01-07 01:06:07 +00:00
Adrian Conlon
c3d2ef51d9 Cycle accuracy for a couple of the indexed write (store) instructions. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2019-01-06 20:39:37 +00:00
Adrian Conlon
4d3be9e756 Use correct boundary crossing conditional for Read/Modify/Write Absolute,X addressing mode. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2019-01-06 12:58:13 +00:00
Adrian Conlon
baf32cef89 Get the memory access more correct for more of boundary crossing indexed addressing modes. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2019-01-06 12:17:43 +00:00
Adrian Conlon
3337f57747 More cycle accuracy changes, concentrating on stack operations. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2019-01-05 23:21:43 +00:00
Adrian Conlon
143e9a9e68 More cycle accuracy changes: 
1) implied instruction, pointless fetch
 2) branch pointless fetch when condition is met

Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2019-01-05 17:23:50 +00:00
Adrian Conlon
556e06426e Further work on the slow migration to a cycle accurate 6502 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2019-01-03 01:04:12 +00:00
Adrian Conlon
5ade05a689 Add a bunch of undocumented 6502 instructions. Abandoned ATX implementation. Too poorly documented. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2018-12-30 12:01:23 +00:00
Adrian Conlon
815c99710a Add enough undocumented 6502 instructions to get through "nestest". 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2018-12-29 22:22:31 +00:00
Adrian Conlon
c136b306ab Use the new busRead/Write processor methods to simplify the 6502 cycle counting. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2018-12-29 22:18:01 +00:00
Adrian Conlon
adb60a6e90 Port the 6502 to the new bus architecture. 2018-12-29 19:40:02 +00:00
Adrian Conlon
dc477cd050 Use explicit enumeration types (improves type safety) where appropriate. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2018-12-01 15:24:29 +00:00
Adrian Conlon
4dc0becb74 Refactor the 6502 implementation to be a lot more like the MC6809. Hopefully show bugs in the latter a little more easily. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2018-10-31 23:29:13 +00:00
Adrian Conlon
fac2da9ac4 Start refactoring CPU cores to use C++17/14 features. (This commit covers the 6502 and Z80) 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2018-10-27 18:41:55 +01:00
Adrian Conlon
1212e8d4f0 Tidy some processor virtual specifications. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2018-08-25 13:35:53 +01:00
Adrian Conlon
c105ee37bf Have a stab at sorting out processor pin handling. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2018-08-25 12:09:26 +01:00
Adrian Conlon
cc64e114a9 Start refactoring the processor classes to allow big/little endian processors to be specified. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2018-08-17 21:53:49 +01:00
Adrian Conlon
70c70af969 Sort out some exception and member initialisation rules. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2018-08-11 21:19:19 +01:00
Adrian Conlon
cac871cf2b Remove duplicated code (from const definitions) the performance benefit isn't worth the amount of duplicated code. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2018-06-24 20:58:20 +01:00
Adrian Conlon
67487b5b6e Simplify the usage of the register16_t union. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2018-06-16 00:55:32 +01:00
Adrian Conlon
3e854c7c49 Const some more bus/processor usage, and ensure the data bus is a member, not a reference to memory. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2018-06-10 00:40:56 +01:00
Adrian Conlon
d818095815 MEMPTR is really only a concept of Intel style processors. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2018-03-18 22:40:23 +00:00
Adrian Conlon
45dc274167 Get rid of wrappers for bus access: i.e. make it clearer where the bus is being read/written. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2018-03-10 01:53:57 +00:00
Adrian Conlon
c6eb68ba13 Further return by value, rather than reference. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2018-02-26 19:47:35 +00:00
Adrian Conlon
adf506a41e Optimisation: Prefer return by value to return by reference. ~10% speed-up! 
Just watch a video by Chandler Carruth from 2015, where he talked about C++ optimisers...

Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2018-02-25 19:48:01 +00:00
Adrian Conlon
9124f10008 6502: Implement some more undocumented instructions (for the Blargg nes cpu tests) 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2018-01-21 10:45:25 +00:00
Adrian Conlon
b5fee5b5d9 Make explicit the notion of page based loads in M6502. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2018-01-18 21:17:45 +00:00
Adrian Conlon
21bd8a06e6 Power on conditions are chip specific and *not* directly related to construction/destruction. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2018-01-18 17:50:15 +00:00
Adrian Conlon
19aea5244b The vector of instructions was good, but a switch is fastest and probably easiest to read/modify. (Running at 101Mz, 32M instructions per second) 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2018-01-17 22:17:08 +00:00
Adrian Conlon
d57cb8c9be 6502: I might regret this, but move to a vector of instructions, rather than decoding them one at a time 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2018-01-16 23:54:43 +00:00
Adrian Conlon
43573ac699 6502: Rotate and shift by value, not reference. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2018-01-14 21:03:29 +00:00
Adrian Conlon
ac95670cfc Add support for 6502 pin 38 (SO: set overflow) 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2018-01-12 20:13:35 +00:00
Adrian Conlon
847e07be86 Add undocumented 6502 instruction RRA. nestest.nes now runs to completion: Hurrah! 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2018-01-07 23:42:26 +00:00
Adrian Conlon
4d9c0b490a Add undocumented 6502 instruction: SRE 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2018-01-07 23:16:24 +00:00
Adrian Conlon
65b856611e Undocumented 6502 instruction RLA added. 
Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
 2018-01-07 22:50:14 +00:00