assets/developer-notes/stephanie-gawroriski/2015/11/26.mkd
# 2015/11/26
***DISCLAIMER***: _These notes are from the defunct k8 project which_
_precedes SquirrelJME. The notes for SquirrelJME start on 2016/02/26!_
_The k8 project was effectively a Java SE 8 operating system and as such_
_all of the notes are in the context of that scope. That project is no_
_longer my goal as SquirrelJME is the spiritual successor to it._
## 00:33
Going to attempt drawing again.
## 07:21
Somehow I am awake early, but I might just sleep again.
## 07:44
Squirrel Quarrel could probably use some refactoring.
## 09:26
Thinking about it, I wonder if method TOCs work with methods. For static it
works, however for instance methods probably not so much. For that I would
have to do something similar then to what I do with instance fields which
is relative from the object base. So for instance fields I must load the
pointer first from memory before it is invoked.
## 09:46
One thing is the efficent handling of interface methods.
## 11:00
I would need some kind of hash lookup table that is simple to use. I can
probably used a fixed size hash table and then on collision just use a kind
of dispatch kind of thing. Since implementation of interfaces is very static
each object can just point to a table of interface data for a specific class,
the class that it is. So this means an extra field in the object data info.
## 11:19
So I am going to need a new reference type, one which when given an interface
gives the offset its interface table will be at in the Class object for a
given instance.
## 11:24
I will need to do a kind of class birthday thing based on all the classes in
the entire library to determine the number of collisions that exist. Then take
that to only include interfaces.
## 11:39
And the results are in:
Of 3912, 0 are shared, 3912 are unique.
So even with all classes they are unique.
## 11:47
Then with all classes in my library:
Of 4847, 0 are shared, 4847 are unique.
So with more with potential sharing they are still unique. So what if I mask
the set of input hashcodes, I wonder then how many matches there will be. This
is to determine an optimal mask so to speak. Perhaps just an AND of the hash
code. So this means there would potentially be more collisions because of this.
## 11:57
And the results are in:
Mask 0x0 ( 0): s 4847 + u 0 = t 4847
Mask 0x1 ( 1): s 4847 + u 0 = t 4847
Mask 0x3 ( 2): s 4847 + u 0 = t 4847
Mask 0x7 ( 3): s 4847 + u 0 = t 4847
Mask 0xf ( 4): s 4847 + u 0 = t 4847
Mask 0x1f ( 5): s 4847 + u 0 = t 4847
Mask 0x3f ( 6): s 4847 + u 0 = t 4847
Mask 0x7f ( 7): s 4847 + u 0 = t 4847
Mask 0xff ( 8): s 4847 + u 0 = t 4847
Mask 0x1ff ( 9): s 4846 + u 1 = t 4847
Mask 0x3ff (10): s 4800 + u 47 = t 4847
Mask 0x7ff (11): s 4381 + u 466 = t 4847
Mask 0xfff (12): s 3411 + u 1436 = t 4847
Mask 0x1fff (13): s 2226 + u 2621 = t 4847
Mask 0x3fff (14): s 1304 + u 3543 = t 4847
Mask 0x7fff (15): s 684 + u 4163 = t 4847
Mask 0xffff (16): s 370 + u 4477 = t 4847
Mask 0x1ffff (17): s 181 + u 4666 = t 4847
Mask 0x3ffff (18): s 84 + u 4763 = t 4847
Mask 0x7ffff (19): s 48 + u 4799 = t 4847
Mask 0xfffff (20): s 20 + u 4827 = t 4847
Mask 0x1fffff (21): s 12 + u 4835 = t 4847
Mask 0x3fffff (22): s 4 + u 4843 = t 4847
Mask 0x7fffff (23): s 4 + u 4843 = t 4847
Mask 0xffffff (24): s 4 + u 4843 = t 4847
Mask 0x1ffffff (25): s 0 + u 4847 = t 4847
Mask 0x3ffffff (26): s 0 + u 4847 = t 4847
Mask 0x7ffffff (27): s 0 + u 4847 = t 4847
Mask 0xfffffff (28): s 0 + u 4847 = t 4847
Mask 0x1fffffff (29): s 0 + u 4847 = t 4847
Mask 0x3fffffff (30): s 0 + u 4847 = t 4847
Mask 0x7fffffff (31): s 0 + u 4847 = t 4847
So this means with every single class that is around, I would need an area that
is 25-bits long to reduce lots of collisions. And that would be a very large
lookup table.
Note that these are just by the class names.
## 12:19
I believe just 64 should be good enough. I suppose I shall also use a shift
down by a bit so the next character is included.
## 12:33
That might not matter much though.
## 12:58
Not doing the shift and using a mask of 64 gives:
Mask 0x3f ( 6, 63): s 4847 + u 0 = t 4847
0x00000000: *******************************......... 80
0x00000001: *************************............... 64
0x00000002: ********************************........ 82
0x00000003: **********************************...... 87
0x00000004: ****************************............ 72
0x00000005: *****************************........... 75
0x00000006: ***********************................. 59
0x00000007: ******************************.......... 77
0x00000008: ***************************............. 70
0x00000009: **************************.............. 67
0x0000000a: *******************************......... 80
0x0000000b: ************************................ 62
0x0000000c: ****************************............ 73
0x0000000d: ***************************............. 70
0x0000000e: ******************************.......... 79
0x0000000f: *****************************........... 75
0x00000010: ****************************............ 73
0x00000011: *******************************......... 80
0x00000012: ********************************........ 84
0x00000013: ***************************............. 71
0x00000014: **********************************...... 88
0x00000015: *****************************........... 75
0x00000016: ***********************************..... 91
0x00000017: ******************************.......... 79
0x00000018: *********************************....... 86
0x00000019: ***************************............. 71
0x0000001a: *************************............... 65
0x0000001b: ***********************************..... 90
0x0000001c: **************************.............. 68
0x0000001d: ***********************................. 59
0x0000001e: ***************************............. 69
0x0000001f: *********************................... 55
0x00000020: *****************************........... 75
0x00000021: ***********************................. 61
0x00000022: ************************................ 62
0x00000023: ******************************.......... 78
0x00000024: *******************************......... 80
0x00000025: **************************.............. 67
0x00000026: *********************************....... 86
0x00000027: ******************************.......... 78
0x00000028: ******************************.......... 78
0x00000029: *****************************........... 74
0x0000002a: ****************************............ 72
0x0000002b: ***************************............. 69
0x0000002c: ************************................ 63
0x0000002d: **********************************...... 87
0x0000002e: ******************************.......... 77
0x0000002f: *****************************........... 74
0x00000030: ********************************........ 82
0x00000031: ********************************........ 84
0x00000032: ********************************........ 84
0x00000033: *************************............... 65
0x00000034: ***********************************..... 91
0x00000035: ********************************........ 82
0x00000036: **************************************** 102
0x00000037: *****************************........... 74
0x00000038: *****************************........... 74
0x00000039: **********************************...... 87
0x0000003a: *************************............... 66
0x0000003b: *******************************......... 80
0x0000003c: ***********************************..... 91
0x0000003d: ****************************............ 73
0x0000003e: ********************************........ 84
0x0000003f: ***************************............. 71
The collisions seem rather small with the entire class library set and quite
even. In the general case there will probably be very few collisions at runtime
when it comes to interfaces. Most classes would generally be unique.
If there are any collisions then there would just have to be a bridge which
calls the right method.
## 17:38
Thanksgiving was rather delicious. There was the following:
* Turkey
* Gravy
* Au Gratin Potatoes
* Mashed Potatoes
* Carrots
* Peas
* Corn
* Bread
And now I am satiated.
## 21:02
Was very tired so I went to sleep.