Data update

Task/Sort-three-variables/EDSAC-order-code/sort-three-variables.edsac

@@ -1,47 +1,81 @@
 [Sort three variables, for Rosetta Code.
- EDSAC, Initial Orders 2]
-[---------------------------------------------------------------------------
- Sorts three 35-bit variables x, y, x, stored at 0#V, 2#V, 4#V respectively.
+ EDSAC, Initial Orders 2.
+--------------------------------------------------------------------------------
+ Sorts three variables x, y, x, stored in consecutive 35-bit locations.
  Uses the algortihm:
     if x > z then swap( x,z)
     if y > z then swap( y,z)
     if x > y then swap( x,y)
  At most two swaps are carried out in any particular case.
- ----------------------------------------------------------------------------]
+ On EDSAC, whether a variable is an integer or a fixed-point real is a matter
+   of interpretation. The integer N has the same bit-pattern as the fixed-point
+   real N*(2^-34). In this program, variables are regarded as integers.
+ NB Integers are here compared by subtraction and noting the sign of the result.
+   It's assumed that the subtraction doesn't overflow the accumulator.
+   This will be OK if the absolute values of the integers are less than 2^33.
+ ------------------------------------------------------------------------------]
 [Arrange the storage]
-            T47K P96F  [M parameter: main routine]
-            T55K P128F [V parameter: variables to be sorted]
+          T55K P56F       [V parameter: variables to be sorted]
+          T46K P62F       [N parameter: print subroutine]
+          T47K P120F      [M parameter: main routine]
 
 [Compressed form of library subroutine R2.
  Reads integers at load time and is then overwritten.]
-            GKT20FVDL8FA40DUDTFI40FA40FS39FG@S2FG23FA5@T5@E4@E13Z
-            T#V     [tell R2 where to store integers]
-[EDIT: List of 35-bit integers separated by 'F', list terminated by '#TZ'.]
-987654321F500000000F123456789#TZ
+          E25K TN  [will be overwritten by the following print subroutine]
+          GKT20FVDL8FA40DUDTFI40FA40FS39FG@S2FG23FA5@T5@E4@E13Z
+          T#V      [tell R2 where to store integers]
+[List of 35-bit integers separated by 'F', list terminated by '#TZ'.
+-12 is entered as -12 + 2^35. Uncomment the desired starting order.]
+ [34359738356F0F77444#TZ]
+ [34359738356F77444F0#TZ]
+ [0F34359738356F77444#TZ]
+ [0F77444F34359738356#TZ]
+  77444F34359738356F0#TZ
+ [77444F0F34359738356#TZ]
+
+[Modified version of library subroutine P7.
+ Prints signed integer left-justified. Integer is passed in 0D.]
+  GKA3FT42@A47@T31@ADE10@T31@A46@T31@SDTDH44#@NDYFLDT4DS43@
+  TFH17@S17@A43@G23@UFS43@T1FV4DAFG48@SFLDUFXFOFFFSFL4FT4DA47@
+  T31@A1FA43@G20@XFT44#ZPFT43ZP1024FP610D@524DO26@XFSFL8FT4DE39@
 
 [Main routine]
-            E25K TM GK
-      [0]   A4#V S#V  [accumulator := z - x]
-            E8@       [skip the swap if x <= z]
-            TD        [0D := z - x]
-            A#V U4#V  [z := x]
-            AD        [acc := old z]
-            T#V       [x := old z]
-      [8]   TF        [clear acc]
-            A4#V S2#V [acc := z - y]
-            E17@      [skip the swap if y <= z]
-            TD        [0D := z - y]
-            A2#V U4#V [z := y]
-            AD        [acc := old z]
-            T2#V      [y := old z]
-     [17]   TF        [clear acc]
-            A2#V S#V  [acc := y - x]
-            E26@      [skip the swap if x <= y]
-            TD        [0D := y - x]
-            A#V U2#V  [y := x]
-            AD        [acc := old y]
-            T#V       [x := old y]
-     [26]   ZF        [halt the machine]
-            EZ        [define entry point]
-            PF        [acc = 0 on entry]
+          E25K TM GK
+    [0]   #F              [figures shift]
+    [1]   NF              [comma (in figures mode)]
+    [2]   !F              [space]
+    [3]   @F              [carriage return]
+    [4]   &F              [line feed]
+    [5]   K4096F          [null]
+       [Enter here with accumulator = 0]
+    [6]   A4#V S#V        [acc := z - x]
+          E14@            [skip the swap if x <= z]
+          TD              [0D := z - x]
+          A#V U4#V        [z := x]
+          AD              [acc := old z]
+          T#V             [x := old z]
+   [14]   TF              [clear acc]
+          A4#V S2#V       [acc := z - y]
+          E23@            [skip the swap if y <= z]
+          TD              [0D := z - y]
+          A2#V U4#V       [z := y]
+          AD              [acc := old z]
+          T2#V            [y := old z]
+   [23]   TF              [clear acc]
+          A2#V S#V        [acc := y - x]
+          E32@            [skip the swap if x <= y]
+          TD              [0D := y - x]
+          A#V U2#V        [y := x]
+          AD              [acc := old y]
+          T#V             [x := old y]
+   [32]   TF              [clear acc]
+       [Print variables after sorting]
+          O@              [set teleprinter to figures mode]
+          A#V TD A36@ GN O1@ O2@  [print 1st variable plus comma, space]
+          A2#V TD A42@ GN O1@ O2@ [print 2nd variable plus comma, space]
+          A4#V TD A48@ GN O3@ O4@ [print 3rd variable plus CR, LF]
+          O5@             [print null to flush teleprinter buffer]
+          ZF              [halt the machine]
+          E6Z             [define entry point]
+          PF              [accumulator = 0 on entry]
 [end]