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45 Commits

Author SHA1 Message Date
Thomas Harte
451f83ba51 Corrects emulation-mode read-modify-writes not to empty the data buffer. 2020-10-09 22:14:42 -04:00
Thomas Harte
0ed98cbfac Attempts to fix direct indirect indexed; not yet successful I think. 2020-10-08 22:15:19 -04:00
Thomas Harte
7dde7cc743 Implements altered direct indexed addressing in emulation mode. 2020-10-08 22:02:14 -04:00
Thomas Harte
0418f51ef2 Takes a shot at emulation-mode 'exceptions'. 
It's just RTI and correct decimal SBC left of the official 6502s now, I think.
 2020-10-08 17:52:13 -04:00
Thomas Harte
054e0af071 Corrects RTS behaviour: the return address on the stack is off by one. 
Dormann's tests now proceed to a BRK.
 2020-10-08 16:55:45 -04:00
Thomas Harte
907c3374c3 Attempts to clean up my JMP/JSR mess. 
Also takes a step forwards in decimal SBC, but it's not right yet.
 2020-10-08 16:48:46 -04:00
Thomas Harte
b608e11965 Realises that not all non-incrementing PC fetches should be thrown away. 2020-10-07 20:06:27 -04:00
Thomas Harte
7439a326a6 Implements BIT (in regular and immediate forms). 2020-10-07 18:15:18 -04:00
Thomas Harte
7065ba4857 Implements the single-byte branches. 2020-10-06 21:24:43 -04:00
Thomas Harte
9ce9167e3c Formalises work left to do. 2020-10-06 19:12:19 -04:00
Thomas Harte
993eff1d3d Starts slowly, with flag manipulation. 2020-10-06 16:25:30 -04:00
Thomas Harte
b7ba0d4327 Attempts to complete all addressing modes. 
So, if bugs didn't exist, it'd just be members of the Operation enum to go.
 2020-10-05 17:04:57 -04:00
Thomas Harte
d8dccf2500 Attempts a full implementation of MVN and MVP. 2020-10-04 19:21:04 -04:00
Thomas Harte
4ebf594b3b This should bring me up to absolute, y. 
i.e. next is datasheet program 7.
 2020-10-04 19:02:47 -04:00
Thomas Harte
8a83024962 Starts a dash towards just completing the addressing modes for now. 
This brings me up to the end of absolute long (i.e. 4a on the datasheet).
 2020-10-04 18:52:46 -04:00
Thomas Harte
bdc1136b96 Edges towards working short absolute addressing mode. 2020-10-03 21:30:24 -04:00
Thomas Harte
b83d93abc2 Accepts that whether instructions do 8- or 16-bit bus accesses depends on either M or X depending on the operation. 2020-10-02 17:08:30 -04:00
Thomas Harte
78b3ec4b10 The actual work begins: starts implementing 65816 micro-ops. 2020-09-29 18:42:07 -04:00
Thomas Harte
ef1a514785 Introduces 6502Selector, for picking either a 6502 or a 65816 based on a single template parameter. 2020-09-28 21:35:46 -04:00
Thomas Harte
6635876e7e Performs a bare factoring out of the 6502 bus handler. 2020-09-28 18:43:53 -04:00
Thomas Harte
5645f90abe Takes a minor first step towards actually performing 65816 instructions. 2020-09-27 22:20:58 -04:00
Thomas Harte
1cd664ad85 Adds a sanity check. 2020-09-26 21:43:26 -04:00
Thomas Harte
e680022b1f Completes the opcode set. 
A million bugs yet to find.
 2020-09-26 21:35:31 -04:00
Thomas Harte
67c2ce2174 Takes a run at completing the stack section. 
I'm not really sure about BRK though — does it gain a signature on the 65816?
 2020-09-26 21:20:01 -04:00
Thomas Harte
596e700b60 Drags myself onto the final page of bus programs. 
233 opcodes now complete; six bus programs to go.
 2020-09-26 20:57:24 -04:00
Thomas Harte
4a53b6e538 Adds push and pull, reaching 229/256 opcodes. 2020-09-26 20:38:29 -04:00
Thomas Harte
687f4bb3bb Adds relative and relative long bus patterns. 
Many of the rest cover only one or two opcodes so this puts me at 216/256 opcodes covered; 35/47 bus programs; just more than 5/7 pages.
 2020-09-26 20:24:50 -04:00
Thomas Harte
473799cb62 There's not a lot to STP and WAI from a bus program point of view. 2020-09-26 20:18:30 -04:00
Thomas Harte
3dc22a9fd5 Adds implied and immediate modes. 
... for 204/256 opcodes covered.
 2020-09-26 17:42:42 -04:00
Thomas Harte
f54b655606 Adds d, x and d, y. 2020-09-26 17:26:17 -04:00
Thomas Harte
d2e868ea2b Adds (d), y; [d], y; and [d]. 
Now covered: 146/256 opcodes, 4/7 pages, 25/47 bus programs.
 2020-09-26 16:55:58 -04:00
Thomas Harte
1512ac11da Adds (d, x) and (d) modes. Albeit by deferring the hard work. 
That's: 122/256 opcodes; 22/47 bus programs, ~3.5/7 pages transcribed. Maybe I'll be able to get to the runtime stuff sooner rather than later?
 2020-09-25 22:22:30 -04:00
Thomas Harte
5039cc7bb2 Adds direct page. 
... to cover 106 opcodes.
 2020-09-25 22:01:36 -04:00
Thomas Harte
5360a7b4ce Adds block moves. 
These are fairly specialised, dealing in two data addresses simultaneously.
 2020-09-25 21:49:03 -04:00
Thomas Harte
2957a31f40 Adds absolute, x; absolute,y; and accumulator addressing modes. 
Now covered: 80/256 opcodes, from 2/6 pages of the data sheet; or 16/47 bus programs.
 2020-09-25 21:16:36 -04:00
Thomas Harte
8c11df52bf Adds absolute long, x. 
Factors out the commonality of a closing read/write while I'm here.
 2020-09-25 19:27:17 -04:00
Thomas Harte
2b7ffcd48f Takes a run at JSL al. 2020-09-25 18:35:00 -04:00
Thomas Harte
125ddfa513 Pays a little attention to runtime storage; completes the first page of bus patterns. 2020-09-25 18:00:02 -04:00
Thomas Harte
22c792dc46 Adds enough logic to start serialising instructions to somewhere. 
Possibly extraneous for now, but it means I can start stepping and testing.
 2020-09-25 17:18:25 -04:00
Thomas Harte
95af1815c8 Completes absolute indexed indirect micro-ops. 
For the record: this is just six out of forty-seven codes complete. Or about two-thirds of six pages. Plenty to do even before I start trying to interpret these things.
 2020-09-24 22:37:31 -04:00
Thomas Harte
d707c5ac95 Switches to generators with stable pointers; adds 2a. 2020-09-24 22:27:20 -04:00
Thomas Harte
5c9192e5e6 Switches to generators for spitting out micro-ops. 
Hopefully with a lot of parts to factor out naturally.
 2020-09-24 17:36:11 -04:00
Thomas Harte
72b5584042 Immediately runs afoul of a read/write difference in the specs between 8/16-bit mode that suggests maybe this isn't a good structure. 
Perhaps generators of some sort?
 2020-09-23 22:28:15 -04:00
Thomas Harte
f9045b5352 Rounds out declaration of the absolutes. 2020-09-23 22:23:23 -04:00
Thomas Harte
f87fe92bc8 Begins a meandering road towards the 65816. 2020-09-23 22:14:42 -04:00