Forth Implementation, Part 3 | Bitwise Episode Guide

0:08Recap and set the stage for the day continuing with our FORTH implementation

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0:08Recap and set the stage for the day continuing with our FORTH implementation

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0:08Recap and set the stage for the day continuing with our FORTH implementation

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1:04Review the dictionary entry data format

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1:04Review the dictionary entry data format

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1:04Review the dictionary entry data format

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3:09Review the find routine, with a mention of its composition begun in higher level C code

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3:09Review the find routine, with a mention of its composition begun in higher level C code

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3:09Review the find routine, with a mention of its composition begun in higher level C code

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9:00Review the current program, noting that find could have been written in FORTH

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9:00Review the current program, noting that find could have been written in FORTH

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9:00Review the current program, noting that find could have been written in FORTH

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11:04Dive into buffered input, beginning in C before adapting it to assembly

22:03Reflect on the intention of this code to be easily translatable from C to assembly

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22:03Reflect on the intention of this code to be easily translatable from C to assembly

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22:03Reflect on the intention of this code to be easily translatable from C to assembly

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22:36Translate our buffered input implementation from C to assembly

33:19twitchplaysp0ng Which registers are callee saved?

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33:19twitchplaysp0ng Which registers are callee saved?

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33:19twitchplaysp0ng Which registers are callee saved?

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33:53davechat I think you need to increment input pointer after char *c = *input; otherwise you have an infinite loop?

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33:53davechat I think you need to increment input pointer after char *c = *input; otherwise you have an infinite loop?

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33:53davechat I think you need to increment input pointer after char *c = *input; otherwise you have an infinite loop?

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34:29Correctly increment input and continue adapting it from C to assembly

37:55Paste our buffered input implementation into forth.asm

39:29Run it to see that it assembles

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39:29Run it to see that it assembles

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39:29Run it to see that it assembles

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39:36twitchplaysp0ng Last comment is wrong. The comment should be sp[-1]

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39:36twitchplaysp0ng Last comment is wrong. The comment should be sp[-1]

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39:36twitchplaysp0ng Last comment is wrong. The comment should be sp[-1]

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39:45Fill our input_buf with the string "foo bar" and try it out

43:09Run it to see what it does

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43:09Run it to see what it does

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43:09Run it to see what it does

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43:33Make our program _drop after doing _putdigit and _getdigit

44:23Print out the address of word_

44:35Step through the simulation to see what it does

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44:35Step through the simulation to see what it does

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44:35Step through the simulation to see what it does

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45:50Renumber the registers

47:26Fix print_hart_state() to display 31 registers (down from 32)

49:29Step through it to see what it does

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49:29Step through it to see what it does

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49:29Step through it to see what it does

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51:14Fix word_ to store back the updated input value

52:43Step through it to see what it does

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52:43Step through it to see what it does

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52:43Step through it to see what it does

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53:29Fix word_ to load the input as a byte (lbu) rather than a word (lw)

54:00Run it to see that it works as expected

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54:00Run it to see that it works as expected

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54:00Run it to see that it works as expected

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55:08Fix word_ to correctly initialise t5 to t4 (char *ptr = start)

55:46Run it to see that we're good

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55:46Run it to see that we're good

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55:46Run it to see that we're good

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56:06Further test our word_ using "per vognsen"

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56:06Further test our word_ using "per vognsen"

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56:06Further test our word_ using "per vognsen"

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57:08twitchplaysp0ng What's it printing?

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57:08twitchplaysp0ng What's it printing?

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57:08twitchplaysp0ng What's it printing?

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58:18Review our bugs in the assembly code

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58:18Review our bugs in the assembly code

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58:18Review our bugs in the assembly code

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1:00:25Introduce _nez word in FORTH, and cmd_seqz() and cmd_snez() instructions in the assembler¹

1:08:30Make our FORTH program call _nez after _word and _find

1:08:53Run it to see all 0s, because neither "per" nor "vognsen" are words in our dictionary

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1:08:53Run it to see all 0s, because neither "per" nor "vognsen" are words in our dictionary

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1:08:53Run it to see all 0s, because neither "per" nor "vognsen" are words in our dictionary

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1:09:06Edit our input buffer to test dictionary matching

1:09:57Run it to see that it all works

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1:09:57Run it to see that it all works

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1:09:57Run it to see that it all works

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1:10:05Introduce _execute word

1:14:08Run it to see that it prints 9

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1:14:08Run it to see that it prints 9

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1:14:08Run it to see that it prints 9

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1:14:18Introduce _xt to push an execution token onto the stack

1:17:36Set up our program to test _xt and _execute

1:18:36Define _0 and _1 to get things going without having an integer parser

1:20:14Run it to see that it does jack shit

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1:20:14Run it to see that it does jack shit

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1:20:14Run it to see that it does jack shit

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1:20:31Print out matching of our test string with the dictionary

1:20:48Run it to see that "1" matches, but "putdigit" doesn't

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1:20:48Run it to see that "1" matches, but "putdigit" doesn't

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1:20:48Run it to see that "1" matches, but "putdigit" doesn't

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1:21:47Change our test string to "1 1 +"

1:21:54Run it to see that the last thing never matches

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1:21:54Run it to see that the last thing never matches

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1:21:54Run it to see that the last thing never matches

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1:22:03Change our test string to "1 1 + putdigit _"

1:22:22Run it to see that "putdigit" never matches

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1:22:22Run it to see that "putdigit" never matches

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1:22:22Run it to see that "putdigit" never matches

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1:22:55Rename the _add word as "+"

1:23:09Run it to see that everything except "putdigit" matches

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1:23:09Run it to see that everything except "putdigit" matches

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1:23:09Run it to see that everything except "putdigit" matches

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1:24:05Define everyone, including _putdigit, before latest_const

1:25:03Run it to see that it works

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1:25:03Run it to see that it works

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1:25:03Run it to see that it works

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1:25:16Enable our FORTH program to execute the words in our string

1:25:44Run it to see what happens

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1:25:44Run it to see what happens

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1:25:44Run it to see what happens

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1:26:51Try testing _xt with known data

1:27:49Run it to see that it prints 9

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1:27:49Run it to see that it prints 9

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1:27:49Run it to see that it prints 9

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1:27:52Label _putdigit putdigit_entry

1:28:20Run it to see that it does not work

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1:28:20Run it to see that it does not work

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1:28:20Run it to see that it does not work

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1:28:27Investigate the problem, presumably in _xt

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1:28:27Investigate the problem, presumably in _xt

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1:28:27Investigate the problem, presumably in _xt

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1:29:39Step through it to see what it's doing

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1:29:39Step through it to see what it's doing

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1:29:39Step through it to see what it's doing

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1:30:57Fix _xt to correctly increment t1

1:32:27Run it to see that it works

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1:32:27Run it to see that it works

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1:32:27Run it to see that it works

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1:33:05Reorganise the program

1:33:58Consider our next steps: reading from the keyboard, and appending definitions for future execution

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1:33:58Consider our next steps: reading from the keyboard, and appending definitions for future execution

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1:33:58Consider our next steps: reading from the keyboard, and appending definitions for future execution

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1:36:43That's it for today

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1:36:43That's it for today

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1:36:43That's it for today

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