X-Git-Url: https://git.stderr.nl/gitweb?p=matthijs%2Fmaster-project%2Freport.git;a=blobdiff_plain;f=Chapters%2FNormalization.tex;h=4b3a08c821404729476f02aefdba5af96c0c1585;hp=1f9f62be9bb633171419c7e4ab4a3c4a82c1d6f3;hb=600d280f5ab94fa48bc84fc13b7d485b868918d3;hpb=b1f08ad1bc712b096ea8330252e7a343955004f7 diff --git a/Chapters/Normalization.tex b/Chapters/Normalization.tex index 1f9f62b..4b3a08c 100644 --- a/Chapters/Normalization.tex +++ b/Chapters/Normalization.tex @@ -1,4 +1,4 @@ -\chapter{Normalization} +\chapter[chap:normalization]{Normalization} % A helper to print a single example in the half the page width. The example % text should be in a buffer whose name is given in an argument. @@ -7,7 +7,7 @@ % will end up on a single line. The strut=no option prevents a bunch of empty % space at the start of the frame. \define[1]\example{ - \framed[offset=1mm,align=right,strut=no]{ + \framed[offset=1mm,align=right,strut=no,background=box,frame=off]{ \setuptyping[option=LAM,style=sans,before=,after=] \typebuffer[#1] \setuptyping[option=none,style=\tttf] @@ -64,7 +64,104 @@ be an input port, every bound value will become a concurrent statement (such as a component instantiation or conditional signal assignment) and the result variable will become the output port. -An example of a program in canonical form would be: +\startbuffer[MulSum] +alu :: Bit -> Word -> Word -> Word +alu = λa.λb.λc. + let + mul = (*) a b + sum = (+) mul c + in + sum +\stopbuffer + +\startuseMPgraphic{MulSum} + save a, b, c, mul, add, sum; + + % I/O ports + newCircle.a(btex $a$ etex) "framed(false)"; + newCircle.b(btex $b$ etex) "framed(false)"; + newCircle.c(btex $c$ etex) "framed(false)"; + newCircle.sum(btex $res$ etex) "framed(false)"; + + % Components + newCircle.mul(btex - etex); + newCircle.add(btex + etex); + + a.c - b.c = (0cm, 2cm); + b.c - c.c = (0cm, 2cm); + add.c = c.c + (2cm, 0cm); + mul.c = midpoint(a.c, b.c) + (2cm, 0cm); + sum.c = add.c + (2cm, 0cm); + c.c = origin; + + % Draw objects and lines + drawObj(a, b, c, mul, add, sum); + + ncarc(a)(mul) "arcangle(15)"; + ncarc(b)(mul) "arcangle(-15)"; + ncline(c)(add); + ncline(mul)(add); + ncline(add)(sum); +\stopuseMPgraphic + +\placeexample[ex:MulSum]{\small{ALU} described in normal form} + \startcombination[2*1] + {\typebufferlam{MulSum}}{Description in normal form} + {\boxedgraphic{MulSum}}{Described architecture} + \stopcombination + +\startbuffer[AddSubAlu] +alu :: Bit -> Word -> Word -> Word +alu = λopcode.λa.λb. + let + res1 = (+) a b + res2 = (-) a b + res = case op of + Low -> res1 + High -> res2 + in + res +\stopbuffer + +\startuseMPgraphic{AddSubAlu} + save opcode, a, b, add, sub, mux, res; + + % I/O ports + newCircle.opcode(btex $opcode$ etex) "framed(false)"; + newCircle.a(btex $a$ etex) "framed(false)"; + newCircle.b(btex $b$ etex) "framed(false)"; + newCircle.res(btex $res$ etex) "framed(false)"; + % Components + newCircle.add(btex + etex); + newCircle.sub(btex - etex); + newMux.mux; + + opcode.c - a.c = (0cm, 2cm); + add.c - a.c = (4cm, 0cm); + sub.c - b.c = (4cm, 0cm); + a.c - b.c = (0cm, 3cm); + mux.c = midpoint(add.c, sub.c) + (1.5cm, 0cm); + res.c - mux.c = (1.5cm, 0cm); + b.c = origin; + + % Draw objects and lines + drawObj(opcode, a, b, res, add, sub, mux); + + ncline(a)(add) "posA(e)"; + ncline(b)(sub) "posA(e)"; + nccurve(a)(sub) "posA(e)", "angleA(0)"; + nccurve(b)(add) "posA(e)", "angleA(0)"; + nccurve(add)(mux) "posB(inpa)", "angleB(0)"; + nccurve(sub)(mux) "posB(inpb)", "angleB(0)"; + nccurve(opcode)(mux) "posB(n)", "angleA(0)", "angleB(-90)"; + ncline(mux)(res) "posA(out)"; +\stopuseMPgraphic + +\placeexample[ex:AddSubAlu]{\small{ALU} described in normal form} + \startcombination[2*1] + {\typebufferlam{AddSubAlu}}{Description in normal form} + {\boxedgraphic{AddSubAlu}}{Described architecture} + \stopcombination \startlambda -- All arguments are an inital lambda @@ -230,10 +327,10 @@ the core language in a notation that resembles lambda calculus. Each of these transforms is meant to be applied to every (sub)expression in a program, for as long as it applies. Only when none of the -expressions can be applied anymore, the program is in normal form. We -hope to be able to prove that this form will obey all of the constraints -defined above, but this has yet to happen (though it seems likely that -it will). +transformations can be applied anymore, the program is in normal form (by +definition). We hope to be able to prove that this form will obey all of the +constraints defined above, but this has yet to happen (though it seems likely +that it will). Each of the transforms will be described informally first, explaining the need for and goal of the transform. Then, a formal definition is @@ -684,7 +781,7 @@ arguments into normal form. The goal here is to: When looking at the arguments of a user-defined function, we can divide them into two categories: \startitemize - \item Arguments with a runtime representable type (\eg bits or vectors). + \item Arguments of a runtime representable type (\eg bits or vectors). These arguments can be preserved in the program, since they can be translated to input ports later on. However, since we can @@ -720,7 +817,7 @@ When looking at the arguments of a builtin function, we can divide them into categories: \startitemize - \item Arguments with a runtime representable type. + \item Arguments of a runtime representable type. As we have seen with user-defined functions, these arguments can always be reduced to a simple variable reference, by the @@ -729,7 +826,7 @@ into categories: functions can be limited to signal references, instead of needing to support all possible expressions. - \item Arguments with a function type. + \item Arguments of a function type. These arguments are functions passed to higher order builtins, like \lam{map} and \lam{foldl}. Since implementing these @@ -973,247 +1070,3 @@ x = let x = add 1 2 in x \stopbuffer \transexample{Return value simplification}{from}{to} - -\subsection{Example sequence} - -This section lists an example expression, with a sequence of transforms -applied to it. The exact transforms given here probably don't exactly -match the transforms given above anymore, but perhaps this can clarify -the big picture a bit. - -TODO: Update or remove this section. - -\startlambda - λx. - let s = foo x - in - case s of - (a, b) -> - case a of - High -> add - Low -> let - op' = case b of - High -> sub - Low -> λc.λd.c - in - λc.λd.op' d c -\stoplambda - -After top-level η-abstraction: - -\startlambda - λx.λc.λd. - (let s = foo x - in - case s of - (a, b) -> - case a of - High -> add - Low -> let - op' = case b of - High -> sub - Low -> λc.λd.c - in - λc.λd.op' d c - ) c d -\stoplambda - -After (extended) β-reduction: - -\startlambda - λx.λc.λd. - let s = foo x - in - case s of - (a, b) -> - case a of - High -> add c d - Low -> let - op' = case b of - High -> sub - Low -> λc.λd.c - in - op' d c -\stoplambda - -After return value extraction: - -\startlambda - λx.λc.λd. - let s = foo x - r = case s of - (a, b) -> - case a of - High -> add c d - Low -> let - op' = case b of - High -> sub - Low -> λc.λd.c - in - op' d c - in - r -\stoplambda - -Scrutinee simplification does not apply. - -After case binder wildening: - -\startlambda - λx.λc.λd. - let s = foo x - a = case s of (a, _) -> a - b = case s of (_, b) -> b - r = case s of (_, _) -> - case a of - High -> add c d - Low -> let op' = case b of - High -> sub - Low -> λc.λd.c - in - op' d c - in - r -\stoplambda - -After case value simplification - -\startlambda - λx.λc.λd. - let s = foo x - a = case s of (a, _) -> a - b = case s of (_, b) -> b - r = case s of (_, _) -> r' - rh = add c d - rl = let rll = λc.λd.c - op' = case b of - High -> sub - Low -> rll - in - op' d c - r' = case a of - High -> rh - Low -> rl - in - r -\stoplambda - -After let flattening: - -\startlambda - λx.λc.λd. - let s = foo x - a = case s of (a, _) -> a - b = case s of (_, b) -> b - r = case s of (_, _) -> r' - rh = add c d - rl = op' d c - rll = λc.λd.c - op' = case b of - High -> sub - Low -> rll - r' = case a of - High -> rh - Low -> rl - in - r -\stoplambda - -After function inlining: - -\startlambda - λx.λc.λd. - let s = foo x - a = case s of (a, _) -> a - b = case s of (_, b) -> b - r = case s of (_, _) -> r' - rh = add c d - rl = (case b of - High -> sub - Low -> λc.λd.c) d c - r' = case a of - High -> rh - Low -> rl - in - r -\stoplambda - -After (extended) β-reduction again: - -\startlambda - λx.λc.λd. - let s = foo x - a = case s of (a, _) -> a - b = case s of (_, b) -> b - r = case s of (_, _) -> r' - rh = add c d - rl = case b of - High -> sub d c - Low -> d - r' = case a of - High -> rh - Low -> rl - in - r -\stoplambda - -After case value simplification again: - -\startlambda - λx.λc.λd. - let s = foo x - a = case s of (a, _) -> a - b = case s of (_, b) -> b - r = case s of (_, _) -> r' - rh = add c d - rlh = sub d c - rl = case b of - High -> rlh - Low -> d - r' = case a of - High -> rh - Low -> rl - in - r -\stoplambda - -After case removal: - -\startlambda - λx.λc.λd. - let s = foo x - a = case s of (a, _) -> a - b = case s of (_, b) -> b - r = r' - rh = add c d - rlh = sub d c - rl = case b of - High -> rlh - Low -> d - r' = case a of - High -> rh - Low -> rl - in - r -\stoplambda - -After let bind removal: - -\startlambda - λx.λc.λd. - let s = foo x - a = case s of (a, _) -> a - b = case s of (_, b) -> b - rh = add c d - rlh = sub d c - rl = case b of - High -> rlh - Low -> d - r' = case a of - High -> rh - Low -> rl - in - r' -\stoplambda - -Application simplification is not applicable.