Forth Implementation, Part 5 | Bitwise Episode Guide

0:08Recap and set the stage for the day focusing on bootstrapping

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0:08Recap and set the stage for the day focusing on bootstrapping

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0:08Recap and set the stage for the day focusing on bootstrapping

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1:39Review the in-progress bootstrapping of the immediate / compilation modality interpretation

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1:39Review the in-progress bootstrapping of the immediate / compilation modality interpretation

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1:39Review the in-progress bootstrapping of the immediate / compilation modality interpretation

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8:16Make "immediate" itself be immediate

9:50Review the new immediate words "else", "begin", "again", "until", "variable" and "constant"

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9:50Review the new immediate words "else", "begin", "again", "until", "variable" and "constant"

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9:50Review the new immediate words "else", "begin", "again", "until", "variable" and "constant"

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14:59Demo the idea behind counter and if-else

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14:59Demo the idea behind counter and if-else

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14:59Demo the idea behind counter and if-else

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16:12Determine to work on "immediate?" with a mention of a "hiding" word

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16:12Determine to work on "immediate?" with a mention of a "hiding" word

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16:12Determine to work on "immediate?" with a mention of a "hiding" word

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18:15Create "immediate?" in FORTH

19:50Run it to find that it works, and remove the hard coded definition

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19:50Run it to find that it works, and remove the hard coded definition

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19:50Run it to find that it works, and remove the hard coded definition

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20:57Consider kicking out the ladder from under us once we're bootstrapped

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20:57Consider kicking out the ladder from under us once we're bootstrapped

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20:57Consider kicking out the ladder from under us once we're bootstrapped

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25:02Define defop2 macro to quickly define binary operators, using it on an "+" operator

26:54Run it to find that it works

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26:54Run it to find that it works

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26:54Run it to find that it works

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27:02Define "-", "and", "or" and "xor" operators

27:46Run it to find that it works

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27:46Run it to find that it works

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27:46Run it to find that it works

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27:56Define defop1 macro to quickly define unary operators, using it to define "0=" and "<>0"

29:53Run it to find that it works

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29:53Run it to find that it works

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29:53Run it to find that it works

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30:05Alias "not" as "0="

31:24Run it to find that it works, but that we may want to bootstrap error checking

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31:24Run it to find that it works, but that we may want to bootstrap error checking

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31:24Run it to find that it works, but that we may want to bootstrap error checking

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31:53Create ">flags"

32:55Run it to find that it broke everything

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32:55Run it to find that it broke everything

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32:55Run it to find that it broke everything

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33:28Make ">flags" just exit for now

33:42Consider creating ">cfa" and integers

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33:42Consider creating ">cfa" and integers

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33:42Consider creating ">cfa" and integers

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35:57Rewrite ">flags"

36:17Run it to find that it now works

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36:17Run it to find that it now works

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36:17Run it to find that it now works

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36:23Revert ">flags" to just exit, and create ">namelen", ">name" and ">cfa"

41:33Run it to find that the live ">cfa" doesn't work

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41:33Run it to find that the live ">cfa" doesn't work

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41:33Run it to find that the live ">cfa" doesn't work

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41:52Test ">namelen" and ">name"

42:05Run it to find that it's okay

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42:05Run it to find that it's okay

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42:05Run it to find that it's okay

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42:26Remove IMMEDIATE and HIDDEN initialisations

42:40Run it to make sure that doesn't break it

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42:40Run it to make sure that doesn't break it

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42:40Run it to make sure that doesn't break it

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42:52Scrutinise ">cfa" and start our investigations by putting the location of the "drop" word on the stack

44:56Run it to see that "drop" is at 1224

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44:56Run it to see that "drop" is at 1224

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44:56Run it to see that "drop" is at 1224

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45:20Try to dup our ">cfa" after finding the "drop" word

45:50Run it to find that the cfa is at 1852402392

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45:50Run it to find that the cfa is at 1852402392

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45:50Run it to find that the cfa is at 1852402392

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46:01Try dereferencing the ">namelen"

46:14Run it to determine that it's already total garbage

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46:14Run it to determine that it's already total garbage

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46:14Run it to determine that it's already total garbage

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46:22Try to dup ">namelen" itself

46:26Run it to see that this is as expected

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46:26Run it to see that this is as expected

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46:26Run it to see that this is as expected

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46:51Make ">cfa" correctly dereference ">namelen" using a byte fetch

47:04Run it to see that it works

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47:04Run it to see that it works

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47:04Run it to see that it works

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48:17Determine to create a general number parser, initially redefining "interpret" and "quit"

51:46Run it to find that it didn't work

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51:46Run it to find that it didn't work

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51:46Run it to find that it didn't work

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52:12Investigate the problem in our new "interpret" and "quit"

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52:12Investigate the problem in our new "interpret" and "quit"

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52:12Investigate the problem in our new "interpret" and "quit"

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57:45Using "break" within [ and ]

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57:45Using "break" within [ and ]

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57:45Using "break" within [ and ]

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58:36Continue to investigate "interpret"

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58:36Continue to investigate "interpret"

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58:36Continue to investigate "interpret"

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59:42Try increasing the stack size

1:00:16Run it to find that it works

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1:00:16Run it to find that it works

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1:00:16Run it to find that it works

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1:00:37Try using our new "quit"

1:00:56Run it to find that it all works, with a few words on recreating more sophisticated definitions

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1:00:56Run it to find that it all works, with a few words on recreating more sophisticated definitions

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1:00:56Run it to find that it all works, with a few words on recreating more sophisticated definitions

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1:02:07Consider building better error handling

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1:02:07Consider building better error handling

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1:02:07Consider building better error handling

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1:03:22Define register-manipulation built-ins "sp@", "sp!", "pc@", "pc!", "rp@" and "rp!"

1:08:04Run it to see that it works

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1:08:04Run it to see that it works

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1:08:04Run it to see that it works

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1:08:08Define "sp0" and "rp0", and introduce an abort function

1:13:28Run it to see that "abort" has put 1234 on the stack, but it ends by crashing in bus_load_word()

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1:13:28Run it to see that "abort" has put 1234 on the stack, but it ends by crashing in bus_load_word()

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1:13:28Run it to see that "abort" has put 1234 on the stack, but it ends by crashing in bus_load_word()

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1:14:08Investigate the crash in "abort"

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1:14:08Investigate the crash in "abort"

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1:14:08Investigate the crash in "abort"

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1:21:33Initialise sp0 and rp0 for the docol routine and "rp0" word to use

1:23:11Run it to see that it is more reasonable

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1:23:11Run it to see that it is more reasonable

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1:23:11Run it to see that it is more reasonable

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1:24:31Prevent "abort" from putting 1234 on the stack, and try to enable it to push the code pointer for "quit" onto the return stack, rather than calling it directly

1:25:08Run it to find that it didn't work

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1:25:08Run it to find that it didn't work

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1:25:08Run it to find that it didn't work

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1:25:49Revert "abort" to just quit

1:26:41Cut off the main stream

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1:26:41Cut off the main stream

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1:26:41Cut off the main stream

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