277 lines
6.7 KiB
Text
277 lines
6.7 KiB
Text
.BP
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.AP "AN EXAMPLE PROGRAM"
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.A 1 0
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.NA
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.ta 4n 8n 12n 16n 20n
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.nf
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1 program example(output);
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2 {This program just demonstrates typical EM code.}
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3 type rec = record r1: integer; r2:real; r3: boolean end;
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4 var mi: integer; mx:real; r:rec;
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5
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6 function sum(a,b:integer):integer;
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7 begin
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8 sum := a + b
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9 end;
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10
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11 procedure test(var r: rec);
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12 label 1;
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13 var i,j: integer;
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14 x,y: real;
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15 b: boolean;
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16 c: char;
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17 a: array[1..100] of integer;
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18
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19 begin
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20 j := 1;
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21 i := 3 * j + 6;
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22 x := 4.8;
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23 y := x/0.5;
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24 b := true;
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25 c := 'z';
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26 for i:= 1 to 100 do a[i] := i * i;
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27 r.r1 := j+27;
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28 r.r3 := b;
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29 r.r2 := x+y;
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30 i := sum(r.r1, a[j]);
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31 while i > 0 do begin j := j + r.r1; i := i - 1 end;
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32 with r do begin r3 := b; r2 := x+y; r1 := 0 end;
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33 goto 1;
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34 1: writeln(j, i:6, x:9:3, b)
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35 end; {test}
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36 begin {main program}
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37 mx := 15.96;
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38 mi := 99;
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39 test(r)
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40 end.
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.fi
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.AD
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.BP
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The EM code as produced by the Pascal-VU compiler is given below. Comments
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have been added manually. Note that this code has already been optimized.
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.A 1 0
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.NA
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.nf
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.ta 1n 24n
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mes 2,2,2 ; wordsize 2, pointersize 2
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\&.1
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rom 't.p\e000' ; the name of the source file
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hol 552,\-32768,0 ; externals and buf occupy 552 bytes
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exp $sum ; sum can be called from other modules
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pro $sum,2 ; procedure sum ; 2 bytes local storage
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lin 8 ; code from source line 8
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ldl 0 ; load two locals ( a and b )
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adi 2 ; add them
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ret 2 ; return the result
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end 2 ; end of procedure ( still two bytes local storage )
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\&.2
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rom 1,99,2 ; descriptor of array a[]
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exp $test ; the compiler exports all level 0 procedures
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pro $test,226 ; procedure test, 226 bytes local storage
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\&.3
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rom 4.8F8 ; assemble Floating point 4.8 (8 bytes) in
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\&.4 ; global storage
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rom 0.5F8 ; same for 0.5
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mes 3,\-226,2,2 ; compiler temporary not referenced by address
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mes 3,\-24,2,0 ; the same is true for i, j, b and c in test
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mes 3,\-22,2,0
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mes 3,\-4,2,0
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mes 3,\-2,2,0
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mes 3,\-20,8,0 ; and for x and y
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mes 3,\-12,8,0
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lin 20 ; maintain source line number
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loc 1
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stl \-4 ; j := 1
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lni ; lin 21 prior to optimization
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lol \-4
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loc 3
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mli 2
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loc 6
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adi 2
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stl \-2 ; i := 3 * j + 6
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lni ; lin 22 prior to optimization
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lae .3
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loi 8
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lal \-12
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sti 8 ; x := 4.8
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lni ; lin 23 prior to optimization
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lal \-12
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loi 8
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lae .4
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loi 8
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dvf 8
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lal \-20
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sti 8 ; y := x / 0.5
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lni ; lin 24 prior to optimization
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loc 1
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stl \-22 ; b := true
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lni ; lin 25 prior to optimization
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loc 122
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stl \-24 ; c := 'z'
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lni ; lin 26 prior to optimization
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loc 1
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stl \-2 ; for i:= 1
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2
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lol \-2
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dup 2
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mli 2 ; i*i
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lal \-224
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lol \-2
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lae .2
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sar 2 ; a[i] :=
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lol \-2
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loc 100
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beq *3 ; to 100 do
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inl \-2 ; increment i and loop
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bra *2
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3
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lin 27
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lol \-4
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loc 27
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adi 2 ; j + 27
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sil 0 ; r.r1 :=
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lni ; lin 28 prior to optimization
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lol \-22 ; b
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lol 0
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stf 10 ; r.r3 :=
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lni ; lin 29 prior to optimization
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lal \-20
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loi 16
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adf 8 ; x + y
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lol 0
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adp 2
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sti 8 ; r.r2 :=
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lni ; lin 23 prior to optimization
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lal \-224
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lol \-4
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lae .2
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lar 2 ; a[j]
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lil 0 ; r.r1
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cal $sum ; call now
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asp 4 ; remove parameters from stack
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lfr 2 ; get function result
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stl \-2 ; i :=
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4
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lin 31
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lol \-2
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zle *5 ; while i > 0 do
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lol \-4
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lil 0
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adi 2
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stl \-4 ; j := j + r.r1
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del \-2 ; i := i - 1
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bra *4 ; loop
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5
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lin 32
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lol 0
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stl \-226 ; make copy of address of r
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lol \-22
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lol \-226
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stf 10 ; r3 := b
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lal \-20
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loi 16
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adf 8
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lol \-226
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adp 2
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sti 8 ; r2 := x + y
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loc 0
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sil \-226 ; r1 := 0
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lin 34 ; note the abscence of the unnecesary jump
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lae 22 ; address of output structure
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lol \-4
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cal $_wri ; write integer with default width
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asp 4 ; pop parameters
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lae 22
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lol \-2
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loc 6
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cal $_wsi ; write integer width 6
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asp 6
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lae 22
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lal \-12
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loi 8
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loc 9
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loc 3
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cal $_wrf ; write fixed format real, width 9, precision 3
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asp 14
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lae 22
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lol \-22
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cal $_wrb ; write boolean, default width
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asp 4
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lae 22
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cal $_wln ; writeln
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asp 2
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ret 0 ; return, no result
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end 226
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exp $_main
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pro $_main,0 ; main program
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\&.6
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con 2,\-1,22 ; description of external files
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\&.5
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rom 15.96F8
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fil .1 ; maintain source file name
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lae .6 ; description of external files
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lae 0 ; base of hol area to relocate buffer addresses
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cal $_ini ; initialize files, etc...
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asp 4
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lin 37
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lae .5
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loi 8
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lae 2
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sti 8 ; mx := 15.96
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lni ; lin 38 prior to optimization
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loc 99
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ste 0 ; mi := 99
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lni ; lin 39 prior to optimization
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lae 10 ; address of r
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cal $test
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asp 2
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loc 0 ; normal exit
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cal $_hlt ; cleanup and finish
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asp 2
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end 0
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mes 5 ; reals were used
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.fi
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.AD
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.A 1 0
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The compact code corresponding to the above program is listed below.
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Read it horizontally, line by line, not column by column.
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Each number represents a byte of compact code, printed in decimal.
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The first two bytes form the magic word.
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.N 1
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.IS 3
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.Dr 33
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173 0 159 122 122 122 255 242 1 161 250 124 116 46 112 0
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255 156 245 40 2 245 0 128 120 155 249 123 115 117 109 160
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249 123 115 117 109 122 67 128 63 120 3 122 88 122 152 122
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242 2 161 121 219 122 255 155 249 124 116 101 115 116 160 249
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124 116 101 115 116 245 226 0 242 3 161 253 128 123 52 46
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56 255 242 4 161 253 128 123 48 46 53 255 159 123 245 30
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255 122 122 255 159 123 96 122 120 255 159 123 98 122 120 255
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159 123 116 122 120 255 159 123 118 122 120 255 159 123 100 128
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120 255 159 123 108 128 120 255 67 140 69 121 113 116 68 73
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116 69 123 81 122 69 126 3 122 113 118 68 57 242 3 72
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128 58 108 112 128 68 58 108 72 128 57 242 4 72 128 44
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128 58 100 112 128 68 69 121 113 98 68 69 245 122 0 113
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96 68 69 121 113 118 182 73 118 42 122 81 122 58 245 32
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255 73 118 57 242 2 94 122 73 118 69 220 10 123 54 118
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18 122 183 67 147 73 116 69 147 3 122 104 120 68 73 98
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73 120 111 130 68 58 100 72 136 2 128 73 120 4 122 112
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128 68 58 245 32 255 73 116 57 242 2 59 122 65 120 20
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249 123 115 117 109 8 124 64 122 113 118 184 67 151 73 118
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128 125 73 116 65 120 3 122 113 116 41 118 18 124 185 67
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152 73 120 113 245 30 255 73 98 73 245 30 255 111 130 58
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100 72 136 2 128 73 245 30 255 4 122 112 128 69 120 104
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245 30 255 67 154 57 142 73 116 20 249 124 95 119 114 105
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8 124 57 142 73 118 69 126 20 249 124 95 119 115 105 8
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126 57 142 58 108 72 128 69 129 69 123 20 249 124 95 119
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114 102 8 134 57 142 73 98 20 249 124 95 119 114 98 8
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124 57 142 20 249 124 95 119 108 110 8 122 88 120 152 245
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226 0 155 249 125 95 109 97 105 110 160 249 125 95 109 97
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105 110 120 242 6 151 122 119 142 255 242 5 161 253 128 125
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49 53 46 57 54 255 50 242 1 57 242 6 57 120 20 249
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124 95 105 110 105 8 124 67 157 57 242 5 72 128 57 122
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112 128 68 69 219 110 120 68 57 130 20 249 124 116 101 115
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116 8 122 69 120 20 249 124 95 104 108 116 8 122 152 120
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159 124 160 255 159 125 255
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.De
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.IE
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