Routines 
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Used by the routine at to_power.
The address of this routine is found in the table of addresses. It is called indirectly via fp_calc_2.
This subroutine handles the function EXP X and is the first of four routines that use the series generator to produce Chebyshev polynomials.
The approximation to EXP X is found as follows:


exp  36C4  RST $28  X  
Perform step i.


36C5  DEFB $3D  re_stack: X (in full floatingpoint form)  
36C6  DEFB $34  stk_data: X, 1/LN 2  
36C7  DEFB $F1,$38,$AA,$3B,$29  
36CC  DEFB $04  multiply: X/LN 2=Y  
Perform step ii.


36CD  DEFB $31  duplicate: Y, Y  
36CE  DEFB $27  int: Y, INT Y=N  
36CF  DEFB $C3  st_mem_3: Y, N (mem3 holds N)  
Perform step iii.


36D0  DEFB $03  subtract: YN=W  
Perform step iv.


36D1  DEFB $31  duplicate: W, W  
36D2  DEFB $0F  addition: 2*W  
36D3  DEFB $A1  stk_one: 2*W, 1  
36D4  DEFB $03  subtract: 2*W1=Z  
Perform step v, passing to the series generator the parameter '8' and the eight constants required.


36D5  DEFB $88  series_08: Z  
36D6  DEFB $13,$36  
36D8  DEFB $58,$65,$66  
36DB  DEFB $9D,$78,$65,$40  
36DF  DEFB $A2,$60,$32,$C9  
36E3  DEFB $E7,$21,$F7,$AF,$24  
36E8  DEFB $EB,$2F,$B0,$B0,$14  
36ED  DEFB $EE,$7E,$BB,$94,$58  
36F2  DEFB $F1,$3A,$7E,$F8,$CF  
At the end of the last loop the 'last value' is 2**W.
Perform step vi.


36F7  DEFB $E3  get_mem_3: 2**W, N  
36F8  DEFB $38  end_calc  
36F9  CALL FP_TO_A  The absolute value of N mod 256 is put into the A register.  
36FC  JR NZ,N_NEGTV  Jump forward if N was negative.  
36FE  JR C,REPORT_6_2  Error if ABS N>+FF.  
3700  ADD A,(HL)  Now add ABS N to the exponent.  
3701  JR NC,RESULT_OK  Jump unless e>+FF.  
Report 6  Number too big.


REPORT_6_2  3703  RST $08  Call the error handling routine.  
3704  DEFB $05  
N_NEGTV  3705  JR C,RSLT_ZERO  The result is to be zero if N<255.  
3707  SUB (HL)  Subtract ABS N from the exponent as N was negative.  
3708  JR NC,RSLT_ZERO  Zero result if e less than zero.  
370A  NEG  Minus e is changed to e.  
RESULT_OK  370C  LD (HL),A  The exponent, e, is entered.  
370D  RET  Finished: 'last value' is EXP X.  
RSLT_ZERO  370E  RST $28  Use the calculator to make the 'last value' zero.  
370F  DEFB $02  delete (the stack is now empty)  
3710  DEFB $A0  stk_zero: 0  
3711  DEFB $38  end_calc  
3712  RET  Finished, with EXP X=0. 
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