Add the addr pseudo-instruction to the assembler and spin the calculator off into a project of its own
This commit is contained in:
CrazyEttin
parent
38080674f5
commit
087c88d8ce
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@ -21,6 +21,16 @@ var
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Bin: array [0 .. $ffef] of byte; //Assembled binary
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Prog: file of byte; //Program file
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//Check if a string is numeric
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function IsNumeric (S: string): boolean;
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var
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I: integer;
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begin
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for I := 1 to length (S) do
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if not (S [I] in ['a' .. 'f', 'A' .. 'F', '0' .. '9']) then exit (false);
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exit (true);
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end;
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//Check if a string is alphanumeric
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function IsAlphaNum (S: string): boolean;
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var
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@ -83,7 +93,7 @@ begin
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end;
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//Assemble an address argument
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procedure AddrArg (I: integer);
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procedure AddrArg (I, A: integer);
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begin
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Offset := 0;
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try
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@ -107,6 +117,8 @@ begin
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if Trim (ExtractDelimited (2, Elem [I], ['-'])) <> '' then Offset := -Offset;
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Elem [I] := Trim (ExtractDelimited (1, Elem [I], ['+', '-']));
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end;
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//Check if the reference is numeric
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if IsNumeric (Elem [I]) = true then ArgError;
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//Check if the reference is alphanumeric
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if IsAlphaNum (Elem [I]) = false then ArgError;
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//Backwards
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@ -122,7 +134,7 @@ begin
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Count := 0;
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while Ref [Count] .Lbl <> '' do Count := Count + 1;
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//Store the reference in the table
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Ref [Count] .Addr := BP + 1;
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Ref [Count] .Addr := BP + A;
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Ref [Count] .Lbl := Elem [I];
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Ref [Count] .Offset := Offset;
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//Placeholder
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@ -130,15 +142,15 @@ begin
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Offset := 0;
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end;
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end;
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if (BP + 2) >= $fff0 then MemError;
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if (BP + 1 + A) >= $fff0 then MemError;
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//Add the offset
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if Addr + Offset >= 0 then begin
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if Addr + Offset <= $ffff then Addr := Addr + Offset
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else ArgError;
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end
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else ArgError;
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Bin [BP + 1] := Addr shr 8;
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Bin [BP + 2] := Addr and $00ff;
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Bin [BP + A] := Addr shr 8;
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Bin [BP + 1 + A] := Addr and $00ff;
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end;
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begin
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@ -260,6 +272,19 @@ begin
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BP := BP + 1;
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end
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//Check for the addr pseudo-instruction
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else if CompareText (ExtractWord (1, Line, [' ']), 'ADDR') = 0 then begin
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//Extract the reference
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Elem [1] := Copy2SpaceDel (Line);
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Elem [2] := Trim (Line);
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//Check if the reference is numeric
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if IsNumeric (Elem [2]) = true then ArgError;
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//Extract and store the address
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AddrArg (2, 0);
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//Increment the byte pointer
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BP := BP + 2;
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end
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//Check for an instruction
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else if Line <> '' then begin
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@ -318,12 +343,12 @@ begin
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//First argument
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OneArgReg (2);
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//Second argument
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AddrArg (3);
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AddrArg (3, 1);
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end;
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//Store
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if Bin [BP] = $b0 then begin
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//First argument
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AddrArg (2);
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AddrArg (2, 1);
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//Second argument
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OneArgReg (3);
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end;
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@ -332,7 +357,7 @@ begin
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//First and second arguments
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TwoArgRegs;
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//Third argument
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AddrArg (4);
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AddrArg (4, 1);
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end;
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//Increment the byte pointer
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@ -1,427 +0,0 @@
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;Hexadecimal adder and subtractor for two-digit unsigned values
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;Print a prompt
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start: load r0, prompt
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store ffff, r0
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load r0, space
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store ffff, r0
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;Read and convert the first argument and store it to arg1
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cleq r0, r0, rarg
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store arg1, r0
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;Print a newline
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cleq r0, r0, newln
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;Read the operation sign
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load r0, ffff
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load r1, plus
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breq r0, r1, storsg
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load r1, minus
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breq r0, r1, storsg
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;Error and halt if the character is not a sign
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breq r0, r0, error
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storsg: store sign, r0
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;Print a space
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load r0, space
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store ffff, r0
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;Read and convert the second argument and load it to r2
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cleq r0, r0, rarg
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xor r2, r2
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xor r2, r0
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;Reload the first argument to r0
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load r0, arg1
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;Print a newline
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cleq r0, r0, newln
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;Print an equals sign
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load r3, equals
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store ffff, r3
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;Check the operation
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load r3, sign
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load r1, minus
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breq r1, r3, brsub
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;Add and load the result to r3
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;Addition
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cleq r0, r0, adder
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;Load the result to r3
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xor r3, r3
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xor r3, r0
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;Skip the subtraction code
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breq r0, r0, nosign
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;Subtract and load the result to r3
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;Subtraction
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brsub: cleq r0, r0, sub
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;Load the result to r3
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xor r3, r3
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xor r3, r0
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;Print a minus sign and unnegate the result if negative
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;Check the sign
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xor r0, r0
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breq r0, r1, nosign
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;Print a minus sign
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load r0, minus
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store ffff, r0
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;Un-negate the result
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store arg1, r3
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load r2, one
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cleq r0, r0, sub
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nand r0, r0
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;Reload the result to r3
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xor r3, r3
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xor r3, r0
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;Skip printing the first digit
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breq r0, r0, skip
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;Print the overflow for addition or zero for positive results of
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;subtraction
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nosign: xor r0, r0
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xor r0, r1
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cleq r0, r0, n2hex
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store ffff, r0
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;Convert and print the result
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;Restore the result back to r0
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skip: xor r0, r0
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xor r0, r3
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;High nibble
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shr r0
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shr r0
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shr r0
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shr r0
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cleq r0, r0, n2hex
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store ffff, r0
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;Restore the result to r0
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xor r0, r0
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xor r0, r3
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;Low nibble
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cleq r0, r0, n2hex
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store ffff, r0
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;Print a newline
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cleq r0, r0, newln
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;Loop
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breq r0, r0, start
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;Error
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error: cleq r0, r0, newln
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load r0, qmark
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store ffff, r0
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cleq r0, r0, newln
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halt
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;Read and convert an argument and load it to r0
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;First digit
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rarg: load r0, ffff
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cleq r0, r0, hex2n
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xor r2, r2
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xor r2, r0
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shl r2
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shl r2
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shl r2
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shl r2
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;Second digit
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rarg2: load r0, ffff
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load r1, backsp
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breq r0, r1, rarg
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cleq r0, r0, hex2n
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;Confirm
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load r3, ffff
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load r1, backsp
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breq r3, r1, rarg2
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load r1, cr
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breq r3, r1, rarg3
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breq r0, r0, error
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;Combine the digits
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rarg3: or r0, r2
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;Return
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ret
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;Print a newline
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newln: load r3, cr
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store ffff, r3
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load r3, lf
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store ffff, r3
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ret
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;Get the value of a hexadecimal digit
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;Locate the hexadecimal digit in the table
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hex2n: load r1, tbl01
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breq r0, r1, val0
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load r1, tbl03
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breq r0, r1, val1
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load r1, tbl05
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breq r0, r1, val2
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load r1, tbl07
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breq r0, r1, val3
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load r1, tbl09
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breq r0, r1, val4
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load r1, tbl0b
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breq r0, r1, val5
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load r1, tbl0d
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breq r0, r1, val6
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load r1, tbl0f
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breq r0, r1, val7
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load r1, tbl11
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breq r0, r1, val8
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load r1, tbl13
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breq r0, r1, val9
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load r1, tbl15
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breq r0, r1, vala
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load r1, tbl17
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breq r0, r1, valb
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load r1, tbl19
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breq r0, r1, valc
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load r1, tbl1b
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breq r0, r1, vald
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load r1, tbl1d
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breq r0, r1, vale
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load r1, tbl1f
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breq r0, r1, valf
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load r1, tbl21
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breq r0, r1, vala
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load r1, tbl23
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breq r0, r1, valb
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load r1, tbl25
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breq r0, r1, valc
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load r1, tbl27
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breq r0, r1, vald
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load r1, tbl29
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breq r0, r1, vale
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load r1, tbl2b
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breq r0, r1, valf
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;Error and halt if the character is not a digit
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breq r0, r0, error
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;Load the value of the hexadecimal digit
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val0: load r0, tbl00
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breq r0, r0, h2nend
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val1: load r0, tbl02
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breq r0, r0, h2nend
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val2: load r0, tbl04
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breq r0, r0, h2nend
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val3: load r0, tbl06
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breq r0, r0, h2nend
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val4: load r0, tbl08
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breq r0, r0, h2nend
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val5: load r0, tbl0a
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breq r0, r0, h2nend
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val6: load r0, tbl0c
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breq r0, r0, h2nend
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val7: load r0, tbl0e
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breq r0, r0, h2nend
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val8: load r0, tbl10
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breq r0, r0, h2nend
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val9: load r0, tbl12
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breq r0, r0, h2nend
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vala: load r0, tbl14
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breq r0, r0, h2nend
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valb: load r0, tbl16
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breq r0, r0, h2nend
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valc: load r0, tbl18
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breq r0, r0, h2nend
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vald: load r0, tbl1a
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breq r0, r0, h2nend
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vale: load r0, tbl1c
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breq r0, r0, h2nend
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valf: load r0, tbl1e
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breq r0, r0, h2nend
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;Return
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h2nend: ret
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;Add r2 to r0 with the overflow stored in r1
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;Reset overflow
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adder: xor r3, r3
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store ovrflw, r3
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;Copy the first argument to r1
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addlop: xor r1, r1
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xor r1, r0
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;Calculate the sum and carry and copy the pre-shift carry to r1
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xor r0, r2
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and r2, r1
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xor r1, r1
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xor r1, r2
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shl r2
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;Check for overflow
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rol r1
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breq r1, r2, nvrflw
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;Store overflow
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load r1, one
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store ovrflw, r1
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;Check for no carry
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nvrflw: breq r2, r3, addend
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;Loop
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breq r0, r0, addlop
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;Load overflow and return
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addend: load r1, ovrflw
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ret
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;Subtract r2 from arg1 and store the result in r0 with the sign
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;bit stored in r1
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;Negate the second argument
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sub: load r0, one
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nand r2, r2
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cleq r0, r0, adder
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;Load the first argument to r2
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load r2, arg1
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;Subtract
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cleq r0, r0, adder
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;Invert the sign bit
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xor r3, r3
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breq r3, r1, submin
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xor r1, r1
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breq r0, r0, subend
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submin: load r1, one
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;Return
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subend: ret
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;Get the hexadecimal digit of a nibble
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;Extract the low nibble
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n2hex: load r1, mask
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and r0, r1
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;Locate the nibble in the table
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load r1, tbl00
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breq r0, r1, dgt0
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load r1, tbl02
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breq r0, r1, dgt1
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load r1, tbl04
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breq r0, r1, dgt2
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load r1, tbl06
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breq r0, r1, dgt3
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load r1, tbl08
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breq r0, r1, dgt4
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load r1, tbl0a
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breq r0, r1, dgt5
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load r1, tbl0c
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breq r0, r1, dgt6
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load r1, tbl0e
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breq r0, r1, dgt7
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load r1, tbl10
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breq r0, r1, dgt8
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load r1, tbl12
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breq r0, r1, dgt9
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load r1, tbl14
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breq r0, r1, dgta
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load r1, tbl16
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breq r0, r1, dgtb
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load r1, tbl18
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breq r0, r1, dgtc
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load r1, tbl1a
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breq r0, r1, dgtd
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load r1, tbl1c
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breq r0, r1, dgte
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load r1, tbl1e
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breq r0, r1, dgtf
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;Load the hexadecimal digit of the nibble
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dgt0: load r0, tbl01
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breq r0, r0, n2hend
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dgt1: load r0, tbl03
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breq r0, r0, n2hend
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dgt2: load r0, tbl05
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breq r0, r0, n2hend
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dgt3: load r0, tbl07
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breq r0, r0, n2hend
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dgt4: load r0, tbl09
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breq r0, r0, n2hend
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dgt5: load r0, tbl0b
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breq r0, r0, n2hend
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dgt6: load r0, tbl0d
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breq r0, r0, n2hend
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dgt7: load r0, tbl0f
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breq r0, r0, n2hend
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dgt8: load r0, tbl11
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breq r0, r0, n2hend
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dgt9: load r0, tbl13
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breq r0, r0, n2hend
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dgta: load r0, tbl15
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breq r0, r0, n2hend
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dgtb: load r0, tbl17
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breq r0, r0, n2hend
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dgtc: load r0, tbl19
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breq r0, r0, n2hend
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dgtd: load r0, tbl1b
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breq r0, r0, n2hend
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dgte: load r0, tbl1d
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breq r0, r0, n2hend
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dgtf: load r0, tbl1f
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breq r0, r0, n2hend
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;Return
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n2hend: ret
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;Characters
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space: data 20
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prompt: data 3e
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plus: data 2b
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minus: data 2d
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equals: data 3d
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qmark: data 3f
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backsp: data 8
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cr: data d
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lf: data a
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;Mask
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mask: data f
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;One
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one: data 1
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;Hexadecimal table
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;Numeric digits
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tbl00: data 0
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tbl01: data 30
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tbl02: data 1
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tbl03: data 31
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tbl04: data 2
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tbl05: data 32
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tbl06: data 3
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tbl07: data 33
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tbl08: data 4
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tbl09: data 34
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tbl0a: data 5
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tbl0b: data 35
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tbl0c: data 6
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tbl0d: data 36
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tbl0e: data 7
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tbl0f: data 37
|
||||
tbl10: data 8
|
||||
tbl11: data 38
|
||||
tbl12: data 9
|
||||
tbl13: data 39
|
||||
;Upper case letter digits
|
||||
tbl14: data a
|
||||
tbl15: data 41
|
||||
tbl16: data b
|
||||
tbl17: data 42
|
||||
tbl18: data c
|
||||
tbl19: data 43
|
||||
tbl1a: data d
|
||||
tbl1b: data 44
|
||||
tbl1c: data e
|
||||
tbl1d: data 45
|
||||
tbl1e: data f
|
||||
tbl1f: data 46
|
||||
;Lower case letter digits
|
||||
tbl20: data a
|
||||
tbl21: data 61
|
||||
tbl22: data b
|
||||
tbl23: data 62
|
||||
tbl24: data c
|
||||
tbl25: data 63
|
||||
tbl26: data d
|
||||
tbl27: data 64
|
||||
tbl28: data e
|
||||
tbl29: data 65
|
||||
tbl2a: data f
|
||||
tbl2b: data 66
|
||||
|
||||
;Variables
|
||||
ovrflw: data 0
|
||||
arg1: data 0
|
||||
sign: data 0
|
||||
10
readme.md
10
readme.md
|
|
@ -66,10 +66,12 @@ Address arguments can be either absolute addresses or references to or
|
|||
relative to a label. Relative references are of the form LABEL +/- N,
|
||||
the spacing being optional.
|
||||
|
||||
In addition to the true instructions there are two pseudo-instructions.
|
||||
ORG defines the starting address of the program: it can only occur as
|
||||
the first instruction and cannot have a label, and is not required if
|
||||
the starting address is 0. DATA introduces a byte of data.
|
||||
In addition to the true instructions there are three
|
||||
pseudo-instructions. ORG defines the starting address of the program: it
|
||||
can only occur as the first instruction and cannot have a label, and is
|
||||
not required if the starting address is 0. DATA introduces a byte of
|
||||
data. ADDR introduces two bytes of data containing the address of its
|
||||
argument, a reference to or relative to a label.
|
||||
|
||||
Note that the assembler does not check for addresses or references to
|
||||
reserved addresses or references to or relative to non-existing labels.
|
||||
|
|
|
|||
Loading…
Reference in New Issue