Applesoft: Internals--Floating Point Math Package (2 of 3)



FLOATING POINT REGISTER MOVE ROUTINES



MOVFM           EAF9

Moves the number in memory Y,A points to into FAC.  On exit A and Z reflect

FACEXP.



MOV2F           EB1E

Pack FAC and temporarily moves it into register 2.  On exit A and Z reflect

FACEXP.



MOV1F           EB21

Pack FAC and moves it temporarily into register 1.  On exit A and Z reflect

FACEXP.



MOVML           EB23

Pack FAC and move it into zero page area starting at X.  On exit A and Z

reflect FACEXP.



MOVMF           EB2B

Pack FAC and move it into memory pointed to by Y,X.  On exit A and Z reflect

FACEXP.



MOVFA           EB53

Move ARG into FAC.  On exit A and Z reflect FACEXP.



MOVAF           EB63

Move FAC into ARG.  On exit A and Z reflect FACEXP.



CONUPK          E9E3

Load ARG from memory pointed to by Y,A.  On exit A and Z reflect

FACEXP.



SUMMARY OF MOVES:



 FAC   => (Y,A)  EB2B    MOVMF

 FAC   => (0,X)  EB23    MOVML

 FAC   => TEMP1  EB21    MOV1F

 FAC   => TEMP2  EB1E    MOV2F

 FAC   =>  ARG   EB63    MOVAF



 ARG   =>  FAC   EB53    MOVFA



 (Y,A) =>  FAC   EAF9    MOVFM

 (Y,A) =>  ARG   E9E3    CONUPK



                      FLOATING POINT OPERATORS



The following routines require that A and Z reflect FACEXP.  Even though FAC

move routines set up A and Z, a LDA $9D will insure their proper values.



FMULT           E97F

Multiply the FAC by the number in memory pointed to by Y,A.



FMULTT          E982

Multipy FAC and ARG.  On entry A and Z must reflect FACEXP.



FDIV            EA66

Divide the number in memory pointed to by Y,A by FAC.



FDIVT           EA69

Divide ARG by FAC.  On entry A and Z must reflect FACEXP.



FADD            E7BE

Add the number Y,A points to in memory to FAC.



FADDT           E7C1

Add FAC and ARG.  On entry A and Z must reflect FACEXP.



FSUB            E7A7

Subtract FAC from the number Y,A points to in memory.



FSUBT           E7AA

Subtract FAC from ARG.  On entry A and Z must reflect FACEXP.



                        TRANSCENDENTAL OPERATORS



FPWRT           EE97

Raise ARG to the FAC power.  On entry A and Z must reflect the value of

FACEXP.



SQR             EE8D

Takes the square root of FAC



LOG             E941

Log base e of FAC



EXP             EF09

Raise e to the FAC power



COS             EFEA

Returns the cosine of the FAC in radians.



SIN             EFF1

Returns the sine of the FAC in radians.



TAN             F03A

Returns the tangent of the FAC in radians.



ATN             F09E

Returns the inverse-tangent of the FAC in radians.



                     OTHER OPERATORS



SGN             EB90

Modifies the value of the FAC depending on its value on entry.  On exit:



      FAC =  1  if FAC was greater than 0

      FAC =  0  if FAC was equal to 0

      FAC = -1  if FAC was less than 0



ABS             EBAF

Absolute value of FAC.  If FAC is less than 0 then FAC = -FAC.



INT             EC23

Greatest integer value of FAC.  Uses QINT and floats the result.



RND             EFAE

Form a pseudo-random number in FAC and update RND at 00C9.



SIGN            EB82

Set A according to the value of FAC.  On exit:



      A = 1  if FAC is positive

      A = 0  if FAC = 0

      A = FF if FAC is negative



FCOMP           EBB2

Compare FAC and a packed number in memory pointed to by Y,A.  On exit:



      A = 1  if (Y,A) < FAC

      A = 0  if (Y,A) = FAC

      A = FF if (Y,A) > FAC



NEGOP           EED0

FAC = -FAC



FADDH           E7A0

Add 1/2 to FAC



DIV10           EA55

Divide FAC by 10. Returns positive numbers only.



MUL10           EA39

Multiply FAC by 10.  Works for both positive and negative numbers.





Apple Tech Notes





Keywords:  <None>



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This information is from the Apple Technical Information Library.



ArticleID: TECHINFO-0000075



19960724 15:55:27.00

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