Logic Design, Part 3 | Bitwise Episode Guide

0:01Recap and set the stage for the day

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0:01Recap and set the stage for the day

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0:01Recap and set the stage for the day

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1:17Consider the balanced reduction tree of our XOR circuit

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1:17Consider the balanced reduction tree of our XOR circuit

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1:17Consider the balanced reduction tree of our XOR circuit

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1:46Associativity

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1:46Associativity

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1:46Associativity

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2:53Delay and circuit depth

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2:53Delay and circuit depth

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2:53Delay and circuit depth

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3:40Compare the linearly- and logarithmically-reduced XOR circuit

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3:40Compare the linearly- and logarithmically-reduced XOR circuit

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3:40Compare the linearly- and logarithmically-reduced XOR circuit

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6:19Demo minimum_delay_reduce() which changes the order in which elements are combined

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6:19Demo minimum_delay_reduce() which changes the order in which elements are combined

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6:19Demo minimum_delay_reduce() which changes the order in which elements are combined

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9:44How minimum_delay_reduce() works

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9:44How minimum_delay_reduce() works

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9:44How minimum_delay_reduce() works

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11:54xanatos387 Is that based on the length of the trace, or something else?

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11:54xanatos387 Is that based on the length of the trace, or something else?

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11:54xanatos387 Is that based on the length of the trace, or something else?

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14:10rygorous xanatos387 The source of the delay is that, in general, other signals are not immediately available: they come out of other combinatorial circuits. So you care about the total delay since the last flip-flop (or similar)

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14:10rygorous xanatos387 The source of the delay is that, in general, other signals are not immediately available: they come out of other combinatorial circuits. So you care about the total delay since the last flip-flop (or similar)

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14:10rygorous xanatos387 The source of the delay is that, in general, other signals are not immediately available: they come out of other combinatorial circuits. So you care about the total delay since the last flip-flop (or similar)

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14:36Simulation and language processing

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14:36Simulation and language processing

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14:36Simulation and language processing

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17:26How modules are defined

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17:26How modules are defined

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17:26How modules are defined

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20:16Set up to define a Copier Visitor for all our node types

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20:16Set up to define a Copier Visitor for all our node types

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20:16Set up to define a Copier Visitor for all our node types

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24:46Handling cycles

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24:46Handling cycles

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24:46Handling cycles

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26:50Define UnaryNode() and InputNode() Copier

29:29Trigger a "Cyclic node graph" error

30:07Enable the UnaryNode Copier to handle cycles

32:03Run it to see that it now works without error

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32:03Run it to see that it now works without error

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32:03Run it to see that it now works without error

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33:04Make all the node initialisers take a type, rather than inferring it

37:23Define ConstantNode(), BinaryNode(), CompareNode() and OutputNode() Copiers

39:45Define InstanceInputNode(), InstanceOutputNode() and Module() Copiers

46:05Define ConcatNode(), IndexNode(), SliceNode() and WhenNode() Copiers

50:13Create Test module, define a set() Copier and introduce copy_module() and make_module()

58:11Test copy_module()

1:01:45Run it to see our module-level copy

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1:01:45Run it to see our module-level copy

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1:01:45Run it to see our module-level copy

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1:02:05Create ModuleInliner()

1:15:06Introduce inline_module() and inline_top_module()

1:20:47Test inline_top_module() to see that it works

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1:20:47Test inline_top_module() to see that it works

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1:20:47Test inline_top_module() to see that it works

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1:21:13Create Xor module for our Test to use

1:22:15Run it to see our encapsulated Xor sub-module

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1:22:15Run it to see our encapsulated Xor sub-module

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1:22:15Run it to see our encapsulated Xor sub-module

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1:22:25Break into ModuleInliner and step through to InstanceOutputNode until realising that we need a default handler

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1:22:25Break into ModuleInliner and step through to InstanceOutputNode until realising that we need a default handler

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1:22:25Break into ModuleInliner and step through to InstanceOutputNode until realising that we need a default handler

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1:23:52Define a default handler in ModuleInliner

1:25:00Continue to step through ModuleInliner to see that it seemed to work

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1:25:00Continue to step through ModuleInliner to see that it seemed to work

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1:25:00Continue to step through ModuleInliner to see that it seemed to work

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1:27:47Consult our graph to see that it isn't right

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1:27:47Consult our graph to see that it isn't right

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1:27:47Consult our graph to see that it isn't right

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1:28:36Change inline_module to return the output operand (not the node)

1:29:32Consult our graph to see that it worked

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1:29:32Consult our graph to see that it worked

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1:29:32Consult our graph to see that it worked

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1:29:44recursivechat A def can have an __init__?

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1:29:44recursivechat A def can have an __init__?

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1:29:44recursivechat A def can have an __init__?

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1:30:340b0000000000000 Can the other x and y inputs be removed?

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1:30:340b0000000000000 Can the other x and y inputs be removed?

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1:30:340b0000000000000 Can the other x and y inputs be removed?

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1:30:50Consider how to prevent the original top-level inputs from being copied

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1:30:50Consider how to prevent the original top-level inputs from being copied

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1:30:50Consider how to prevent the original top-level inputs from being copied

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1:32:54Step through ModuleInliner to see what's happening with the original inputs

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1:32:54Step through ModuleInliner to see what's happening with the original inputs

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1:32:54Step through ModuleInliner to see what's happening with the original inputs

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1:36:24Dive into Test2 and determine that the inputs are not related to the ones that are externally hooked up

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1:36:24Dive into Test2 and determine that the inputs are not related to the ones that are externally hooked up

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1:36:24Dive into Test2 and determine that the inputs are not related to the ones that are externally hooked up

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1:40:27Note that the input duplication is only related to the sub-module

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1:40:27Note that the input duplication is only related to the sub-module

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1:40:27Note that the input duplication is only related to the sub-module

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1:41:01Change the Module() Copier to put the copied self(node) - as opposed to the original node - into the instance_inputs array

1:41:11Run it to see that that fixed it

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1:41:11Run it to see that that fixed it

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1:41:11Run it to see that that fixed it

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1:42:13Create an And module for our Xor to use, and so test sub-module inlining

1:43:39Run it to see that that works, and reflect on the simplicity of our Copier

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1:43:39Run it to see that that works, and reflect on the simplicity of our Copier

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1:43:39Run it to see that that works, and reflect on the simplicity of our Copier

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1:45:02Create CyclicTest module torture test

1:47:45Run it to see our cycle

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1:47:45Run it to see our cycle

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1:47:45Run it to see our cycle

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1:48:13Test inlining the CyclicTest, hit a "Cyclic node graph" error and consider how to resolve it

1:51:12Create WireNode

1:54:02Test WireNode

1:55:25Run it and explain the idea behind wires

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1:55:25Run it and explain the idea behind wires

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1:55:25Run it and explain the idea behind wires

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1:56:07Make the InstanceOutputNode() ModuleInliner use wires, and define a WireNode() Copier

1:57:30Run it on Test2 to see that nothing broke

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1:57:30Run it on Test2 to see that nothing broke

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1:57:30Run it on Test2 to see that nothing broke

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1:58:20Run it on CyclicTest and see that the wires don't resolve our "Cyclic node graph" error

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1:58:20Run it on CyclicTest and see that the wires don't resolve our "Cyclic node graph" error

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1:58:20Run it on CyclicTest and see that the wires don't resolve our "Cyclic node graph" error

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2:00:39Simplify the InstanceOutputNode() Copier and make the Module() Copier create temporary wires

2:04:14Step through the Copier to see how it all handles CyclicTest

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2:04:14Step through the Copier to see how it all handles CyclicTest

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2:04:14Step through the Copier to see how it all handles CyclicTest

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2:04:58Change the Module() Copier to put the output items (rather than the connections) as wires into the instance_outputs array

2:05:24Continue to step through the Copier

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2:05:24Continue to step through the Copier

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2:05:24Continue to step through the Copier

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2:08:13Change the Module() Copier to put all the result.items() into the instance_outputs array

2:08:54Run it to see that our cyclic module works

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2:08:54Run it to see that our cyclic module works

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2:08:54Run it to see that our cyclic module works

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2:09:03Run it to see that our inlined cyclic module also works

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2:09:03Run it to see that our inlined cyclic module also works

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2:09:03Run it to see that our inlined cyclic module also works

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2:09:26Create WireRemover using a newly introduced remove_wires()

2:10:54Test remove_wires() to see that that works too

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2:10:54Test remove_wires() to see that that works too

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2:10:54Test remove_wires() to see that that works too

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2:11:58Wind it down with a mention of the After Hours streams

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2:11:58Wind it down with a mention of the After Hours streams

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2:11:58Wind it down with a mention of the After Hours streams

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