;*********************************************** ;Floating point division of two unsigned integer ;8 bit variables ; ;Input: AARGB0 - dividend (nominator) ; BARGB0 - divisor (denominator) ;Output: ; AEXP, AARGB0, AARGB1 - quotient ; (MICROCHIP format - AN575) ; w = 0 on success ; w = 1 error: divide by zero ;Temporaries: ; BARGB1 ; ;RAM - 5 bytes ;ROM - 41 words ;Speed - 7+4+8*10-2+5+14*25-2+4+3 = 449 instruction ; cycles worst case (including call and return) ;*********************************************** fdiv24_8_8 mov W, BARGB0 snb Z retw #1 ;divide by zero clr AEXP mov W, AARGB0 snb Z retw #0 ;zero result ;loop to use all 8 bits of dividend (integer 8 by 8 divide) mov AARGB1, W clr BARGB1 mov W, #$08 mov AARGB0, W ;aargb0 is used as loop counter fdiv24_8_8b rl AARGB1 rl BARGB1 mov W, BARGB0 mov W, BARGB1-w snb C mov BARGB1, W decsz AARGB0 jmp fdiv24_8_8b rl AARGB1 ;aargb1 is the integer quotient so far ;loop to fill all the bits of 16bit mantissa clr AARGB0 mov W, #$8E mov AEXP, W clrb C fdiv24_8_8c rl BARGB1 mov W, BARGB0 sb C ;check carry (9th bit) jmp fdiv24_8_8d sub BARGB1, W setb C jmp fdiv24_8_8e fdiv24_8_8d mov W, BARGB1-w snb C mov BARGB1, W fdiv24_8_8e rl AARGB1 rl AARGB0 dec AEXP sb AARGB0.7 jmp fdiv24_8_8c clrb AARGB0.7 ;replace explicit msb with sign retw #0 ;*********************************************** ; Nikolai http://techref.massmind.org/member/NG--944
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