;******************************************************************************* ; Input: packed BCD in bcd2:bcd1:bcd0 (modified!) ; bcd0 = tens:ones ; bcd1 = thou:hund ; bcd2 = 0:tenk ; Output: 16 bit binary in hi:lo ;Temporary: counter ; Size: 23 instructions ; Timing: 3+2+16*(6+12+4)-2+3=358 instruction cycles ; ; Notes: The routine uses BCD division by 2. Each iteration ; the LSB of BCD value (which coincides with correspondent ; binary bit) is shifted to output and BCD value is ; divided by 2. To do the division, BCD is shifted right ; once and corrected. Correction: if MSB of a nibble is set, ; subtract 3 from it. ; ;January 22, 2001 by Nikolai Golovchenko ;******************************************************************************* bcd2bin16 mov W, #16 mov counter, W bcd2bin16loop clc rr bcd2 rr bcd1 rr bcd0 rr hi rr lo clr W snb bcd0.3 or W, #$03 snb bcd0.7 or W, #$30 sub bcd0, W clr W snb bcd1.3 or W, #$03 snb bcd1.7 or W, #$30 sub bcd1, W decsz counter jmp bcd2bin16loop ret ;*******************************************************************************
file: /Techref/scenix/lib/math/radix/bcd2bin16.htm, 1KB, , updated: 2004/6/10 14:40, local time: 2024/8/14 16:04,
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