Working first version!

2 files changed, 247 insertions, 42 deletions

diff --git a/algorithm.txt b/algorithm.txt
index 109a7b1..a810953 100644
--- a/algorithm.txt
+++ b/algorithm.txt
@@ -11,6 +11,8 @@ Mmarker: [ 1 | qcurrent | t1 | t2 | t3 ]
 Tape
 - Each cell: [ 0 | head | tt1 | tt2 | sym ]
 
+EXPLICITLY USED: sizeof(rule) == 2 * sizeof(cell)
+
 
 Read input
 ==========
@@ -19,56 +21,77 @@ Write 1, move right a rule width
 Go to tr1
 Write 1
 While nonzero:
+	Subtract 1 from tr1
 	Read into qfrom
-
-	Read into sread
-	Copy to sread+1 (scratch sread+2)
-	Write 1 to sread+2
-	Subtract 32 from sread+1 and go to sread+1
+	Copy to tr4 (using tr3 as scratch)
+	Write 1 to tr3  ("should zero qfrom")
+	Go to tr4 and add 1
 	While nonzero:
-		Subtract 1 from sread+2
-		Zero sread+1 and go to sread+1
-	Go to sread+2
-	While nonzero:
-		Zero sread
-		Zero sread+2 and go to sread+2
-	Go to sread
+		Zero tr4
+		Subtract 1 from tr3
+		Write 1 to rightrule.tr1
 
-	Read into qto
+		Read into sread
+		Copy to sread+1 (scratch sread+2)
+		Write 1 to sread+2
+		Subtract 32 from sread+1 and go to sread+1
+		While nonzero:
+			Subtract 1 from sread+2
+			Zero sread+1 and go to sread+1
+		Go to sread+2
+		While nonzero:
+			Zero sread
+			Zero sread+2 and go to sread+2
 
-	Read into swrite
-	Copy to swrite+1 (scratch swrite+2)
-	Write 1 to swrite+2
-	Subtract 32 from swrite+1 and go to swrite+1
-	While nonzero:
-		Subtract 1 from swrite+2
-		Zero swrite+1 and go to swrite+1
-	Go to swrite+2
-	While nonzero:
-		Zero swrite
-		Zero swrite+2 and go to swrite+2
-	Go to swrite
+		Read into qto
 
-	Read into dir
-	Subtract '=' (61) from dir
-	Copy qfrom to tr4 (using tr3 as scratch)
-	Go to tr4
-	While nonzero:
-		Add 1
+		Read into swrite
+		Copy to swrite+1 (scratch swrite+2)
+		Write 1 to swrite+2
+		Subtract 32 from swrite+1 and go to swrite+1
 		While nonzero:
-			Write 1 to rightrule.tr1
-			Zero tr4
-		Zero tr4
+			Subtract 1 from swrite+2
+			Zero swrite+1 and go to swrite+1
+		Go to swrite+2
+		While nonzero:
+			Zero swrite
+			Zero swrite+2 and go to swrite+2
+
+		Read into dir
+		Subtract '=' (61) from dir
+
+		Go to tr4
+
+	Go to tr3
+	While nonzero:
+		Zero qfrom
+		Zero tr3 and go to tr3
 
 	Go to rightrule.tr1, which is 1 precisely if we didn't have EOF
 
-Now at a zero tr1 that is really the qcurrent of Mmarker
+Now at a zero tr1 that is one rule width too far.
+So go one rule width left, at which point we are on the qcurrent of Mmarker.
 Write 'S' (83), and go to Mmarker.0
 Write 1
 Set rightcell.head to 1
 Go back to Mmarker.0
 
 
+Main loop
+=========
+
+Precondition: cursor at Mmarker.0 and all temporaries are 0
+
+Subtract 'H' from qcurrent (using t1 as scratch)
+While qcurrent is nonzero:
+	Add 'H' to qcurrent
+	Go to Mmarker.0
+
+	Perform execution step
+
+	Subtract 'H' from qcurrent
+
+
 Execution step
 ==============
 
@@ -77,7 +100,7 @@ Precondition: cursor at Mmarker.0 and all temporaries are 0
 Find cell with head=1:
 	Set t1 to 1
 	While nonzero:
-		Zero current cell (leftrule.tt1), then move right a rule width; now at tt1
+		Zero current cell (leftrule.tt1), then move right a cell width; now at tt1
 		Set tt1 to 1
 		Move head to tt1 (multiplier -1) and tt2, move tt2 back to head
 		Now tt1 is not(head).
@@ -89,7 +112,7 @@ Move tt1 over tt1's back to t1:
 	Go to tt2, set to 1
 	While nonzero:
 		Zero current cell (tt2)
-		Set leftcell.tt1 to 1
+		Set leftcell.tt2 to 1
 		Move leftcell.0 to leftcell.tt2 (multiplier -1) and leftcell.tt1
 		Move leftcell.tt1 back to leftcell.0
 		Move tt1 to leftcell.tt1
@@ -97,8 +120,9 @@ Move tt1 over tt1's back to t1:
 	Now at zero t2, and t1 is sym.
 [t1 = sym; tt1 = tt2 = 0 for all cells]
 
-Copy qcurrent and t1 (=sym) to tr1 and tr2 of last rule (using t2 as scratch)
-Move to t2 (same offset as tr3), set to 1
+Copy qcurrent to tr1 of last rule (using t2 as scratch)
+Move t1 (=sym) to tr2 of last rule
+Go to t2 (same offset as tr3), set to 1
 While nonzero:
 	Zero current cell (rightrule.tr3), then move left a rule width; now at tr3
 	Zero tr3
@@ -126,6 +150,7 @@ While nonzero:
 	[tr1 = qcurrent, tr2 = sym, tr3 = q!=q || s!=s, leftrule.tr3 = q!=q || s!=s]
 	While leftrule.0 is nonzero:
 		Zero tr3 and set tr4 to 1
+		Zero leftrule.0
 	Move tr4 to leftrule.0
 
 	[tr1 = qcurrent, tr2 = sym, tr3 = (q!=q || s!=s) && not_leftmost_rule, leftrule.tr3 = q!=q || s!=s]
@@ -139,7 +164,7 @@ While leftrule.tr3:
 	Apparently no rule matched, so crash().
 
 Apparently leftrule.tr3 is zero, so the current rule matches.
-Zero tr1 and tr2
+Zero leftrule.tr1 and leftrule.tr2
 Copy qto to tr2 (using tr1 as scratch)
 Copy swrite to tr3 (using tr1 as scratch)
 Copy dir to tr4 (using tr1 as scratch)
@@ -151,9 +176,9 @@ While nonzero:
 	Move tr3 back to rule.0
 	Move tr2 to rightrule.tr2
 	Move leftrule.tr2 to tr2, leftrule.tr3 to tr3, leftrule.tr4 to tr4
-	Go to rightrule.tr2
+	Go to rightrule.tr2 (or tt1 of second cell! Here we use that sizeof(rule) == 2 * sizeof(cell))
 
-Now: [t1 = qto, t2 = swrite, t3 = dir] and cursor is at t1.
+Now: [t1 = qto, t2 = swrite, t3 = dir] and cursor is at tt1 of second cell.
 
 Zero qcurrent
 Move t1 to qcurrent
diff --git a/bfturing.bf b/bfturing.bf
new file mode 100644
index 0000000..536dd51
--- /dev/null
+++ b/bfturing.bf
@@ -0,0 +1,180 @@
+READ INPUT
+
++ >>>>>>>>>>
+> +
+[
+	-
+	>>>> ,
+	[-<+<+>>]<<[->>+<<]
+	+
+	> +
+	[
+		[-]
+		< -
+		>>>>>>>> +
+
+		<<<<< ,
+		[->+>+<<]>>[-<<+>>]
+		+
+		< --------------------------------
+		[>-<[-]]
+		> [<<[-]>>[-]]
+		< ,
+		> ,
+		[->+>+<<]>>[-<<+>>]
+		+
+		< --------------------------------
+		[>-<[-]]
+		> [<<[-]>>[-]]
+
+		< ,
+		>++++++[-<---------->]<-
+
+		<<<<<
+	]
+
+	<
+	[ >> [-] << [-] ]
+
+	>>>>>>>>
+]
+
+<<<<<<<<<<
+
+>+++++++[-<++++++++++++>]<- <
++
+>>>>>> + <<<<<<
+
+
+MAIN LOOP
+
+>>++++++++[-<--------->]<
+[
+	>++++++++[-<+++++++++>]<<
+
+	EXECUTION STEP
+
+	>> +
+	[
+		- >>>>> +
+		<[->->+<<]>>[-<<+>>]<
+	]
+	<<
+
+	>>>> [-<+<+>>]<[->+<]
+	+
+	[
+		-
+		<<<<< +
+		<<< [->>+>-<<<] >> [-<<+>>]
+		>>>>> [-<<<<<+>>>>>] <<<<
+	]
+
+	<< [-<<<<<<<<<<+>>>>>>>>>> >>+<<] >>[-<<+>>]
+	< [-<<<<<<<<<<+>>>>>>>>>>]
+	> +
+	[
+		[-] <<<<<<<<<< [-]
+		>> [-<+<+>>]<<[->>+<<]
+		<< [-<+>>>+<<]<[->+<]
+		>>> [->-<]>[<+>[-]]
+		< [-<<<<<<<<<<+>>>>>>>>>>]
+
+		>>> [-<<+<+>>>]<<<[->>>+<<<]
+		< [-<<+>>>+<]<<[->>+<<]
+		>>> [->-<]>[<+>[-]]
+		< [-<<<<<<<<<+>>>>>>>>>]
+
+		<<<<<<<<<< [->>>>>>>>>>>+<<<<<<<<<<<]
+		> [->>>>>>>>>>+<<<<<<<<<<] >>>>>>>>>>
+		[[-]<+>]
+
+		< [-<<<+<<<<<<<+>>>>>>>>>>]<<<[->>>+<<<]
+
+		<<<<<<<<<< [>>>>>>>>>> >>>[-]>+<<<< <<<<<<<<<<-]
+		>>>>>>>>>> >>>> [-<<<< <<<<<<<<<<+>>>>>>>>>> >>>>]
+
+		<<< [-<<<<<<<<<<+>>>>>>>>>>]
+		> [-<<<<<<<<<<+>>>>>>>>>>]
+		>
+	]
+
+	<<<<<<<<<<
+	[$]  CRASH
+
+	<< [-] > [-]
+	>>>>>>>>>> >>>>> [-<<<<<+<+>>>>>>]<<<<<<[->>>>>>+<<<<<<]
+	>>>>>>> [-<<<<<+<<+>>>>>>>]<<<<<<<[->>>>>>>+<<<<<<<]
+	>>>>>>>> [-<<<<<+<<<+>>>>>>>>]<<<<<<<<[->>>>>>>>+<<<<<<<<]
+
+	>>>>>>>>>>> +
+	[
+		<< [->>->+<<<] >>> [-<<<+>>>]
+		< [->>>>>>>>>>+<<<<<<<<<<]
+		<<<<<<<<<< [->>>>>>>>>>+<<<<<<<<<<]
+		> [->>>>>>>>>>+<<<<<<<<<<]
+		> [->>>>>>>>>>+<<<<<<<<<<]
+		>>>>>>>> >>>>>>>>>>
+	]
+
+	<<<<<<<<<<
+
+	< [-]
+	> [-<+>]
+	> [-<+>] > [-<+>]
+
+	>>> +
+	[
+		< [->->+<<] >> [-<<+>>]
+		< [->>>>>+<<<<<]
+		<<<<< [->>>>>+<<<<<] > [->>>>>+<<<<<] >>>>
+		>>>>>
+	]
+
+	<<<<<
+
+	>> [-]
+	<< [->>+<<]
+
+	> [-<+<<+>>>] <<< [->>>+<<<]
+
+	>>
+	[
+		-
+		[<<+>>[-]]
+	]
+
+	>
+	[
+		+
+		[<+>[-]]
+	]
+
+	<<<
+	[
+		<<<<<
+		[$]  CRASH
+		>>>>>> [-<<<<<+>>>>>]
+		< [-]
+	]
+
+	>>
+	[
+		< [->>>>>+<<<<<]
+		> [-]
+	]
+
+	+
+	[
+		-
+		<<<<< +
+		<< [->>->+<<<] >>> [-<<<+>>>]
+		<
+	]
+
+	<<
+
+
+	FINAL PART OF MAIN LOOP
+	>>++++++++[-<--------->]<
+]