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8-Bit Software

The BBC and Master Computer Public Domain Library

A9CF LOG

Submitted by Steve Fewell

Description:

Call the &A746 routine to get the Float value and obtain the result calculation for LN.
Jump to &A9A3 with A = &42 and Y = &BF to multiply the FWA by the Floating-Point
constant at location &BF42 in the Floating-Point constant table.
The constant value at &BF42 is 0.434294482. This value is 1/Log(10). Multiplying the LN result
by this value gives the LOG result.


Disassembly for the LOG routine

A9CF F 032 070 167 20 46 A7 JSR &A746 LN
A9D2 B 169 066 A9 42 LDA#&42
A9D4   160 191 A0 BF LDY#&BF
A9D6   128 203 80 CB BRA -53 --> &A9A3 Multiply FWA by &BF42 (0.434294482)

 


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