;[Division][16_16_16]

;FlameCyclone 20181120

Dividend_L = $00 ;被除數(shù)低位

Dividend_H = Dividend_L + 1 ;被除數(shù)高位

Divisor_L = $02 ;除數(shù)低位

Divisor_H = Divisor_L + 1 ;除數(shù)高位

Quotient_L = $04 ;最終商低位

Quotient_H = Quotient_L + 1 ;最終商高位

Multiple_L = $06 ;位倍數(shù)低位

Multiple_H = $07 ;位倍數(shù)高位

;65535/1耗時(shí)1562

;65535/255耗時(shí)467

;65535/65535耗時(shí)120

;Division

?.ORG $8000

?

?LDA #255

?STA Dividend_L

?LDA #255

?STA Dividend_H

?LDA #255

?STA Divisor_L

?LDA #255

?STA Divisor_H

?JSR Division

?RTS

Division: ;除法計(jì)算

?LDA #$01

?STA Multiple_L

?LDX #$00

?STX Multiple_H

?STX Quotient_L

?STX Quotient_H

?

?LDA Divisor_L

?BNE Multiple_Set

?LDA Divisor_H

?BEQ Division_End

Multiple_Set:

?LDA Divisor_H

?BMI Compare

?BNE Align_Bits

?LDA Divisor_L

?STA Divisor_H

?STX Divisor_L

?STX Multiple_L

?INC Multiple_H

?LDX #$08

?LDA Divisor_H

?BMI Compare

Align_Bits: ;被除數(shù)與除數(shù)左端對(duì)齊

?INX

?ASL Multiple_L

?ROL Multiple_H

?ASL Divisor_L

?ROL Divisor_H

?BPL Align_Bits

Compare: ;被除數(shù)與除數(shù)比較

?LDA Dividend_H

?CMP Divisor_H

?BCC MoveBits_Right

?BNE Subtraction_L1

?LDA Dividend_L

?CMP Divisor_L

?BCS Subtraction

MoveBits_Right:

?LSR Divisor_H

?ROR Divisor_L

?LSR Multiple_H

?ROR Multiple_L

?JMP Compare

?

Subtraction: ;被除數(shù)-除數(shù)

?LDA Dividend_H

Subtraction_L1:

?SBC Divisor_H

?STA Dividend_H

?LDA Dividend_L

?SBC Divisor_L

?STA Dividend_L

Accumulation:

?LDA Quotient_L ;商 = 商 | 位倍數(shù)

?ORA Multiple_L

?STA Quotient_L

?LDA Quotient_H

?ORA Multiple_H

?STA Quotient_H

?DEX

?BMI Division_End

?LDA Dividend_L

?BNE MoveBits_Right

?LDA Dividend_H

?BNE MoveBits_Right

Division_End: ;乘法計(jì)算結(jié)束

?RTS