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Text File | 1984-04-29 | 28.2 KB | 649 lines

NAME FLPT CSEG PUBLIC OVERF,FLOAD,FSTOR,FADD,FSUB,FMUL,FDIV,FTEST PUBLIC FCHS,FABS,RSH,LSH,ADD10,FZERO,FCOMP,FSTR0 EXTRN OVER,PREX,ACCE,ACCS,ACC1,ACC2,ACC3,SF ; 8008 BINARY FLOATING POINT SYSTEM ; ARITHMETIC AND UTILITY PACKAGE ; PROGRAMMER CAL OHME ; DATE 26 DECEMBER 1973 ; FSTOR SUBROUTINE ENTRY POINT. FSTR0: MOV M,E; STORE ZEROETH WORD INR L; TO ADDRESS FIRST WORD FSTOR: MOV M,A; STORE FIRST WORD STR1: INR L; TO ADDRESS SECOND WORD MOV M,B; STORE SECOND WORD INR L; TO ADDRESS THIRD WORD MOV M,C; STORE THIRD WORD INR L; TO ADDRESS FOURTH WORD MOV M,D; STORE FOURTH WORD RET ; RETURN TO CALLER ; FLOATING POINT ZERO SUBROUTINE ENT. PNT. FZERO: LXI H,ACCE; TO ADDRESS ACCUM EXPONENT XRA A; ZERO MOV M,A; CLEAR ACCUMULATOR EXPONENT RET ; RETURN TO CALLER ; FLOATING POINT CHS SUBROUTINE ENT. PNT. FCHS: MVI A,80H; MASK FOR SIGN BIT DB 00EH; LBI INST TO SKIP NEXT WD ; FLOATING POINT ABS SUBROUTINE ENT. PNT. FABS: XRA A; ZERO LXI H,ACCS; TO ADDRESS ACCUM SIGN ANA M ; COMPLEMENT OF SIGN XRI 80H; COMPLEMENT THE SIGN BIT MOV M,A; ACCUMULATOR SIGN ; FLOATING POINT TEST ENTRY POINT. FTEST: LXI H,ACCE; TO ADDR ACCUM EXPONENT MOV A,M; ACCUMULATOR EXPONENT ANA A ; SET CONTROL BITS JZ FZERO; IF ACCUMULATOR IS ZERO MOV E,A; ACCUMULATOR EXPONENT INR L; TO ADDR ACCUMULATOR SIGN MOV A,M; ACCUMULATOR SIGN INR L; TO ADDR ACCUM 1ST FRCTN XRA M; ACCUM SIGN AND 1ST FRCTN INR L; TO ADDR ACCUM 2ND FRCTN MOV C,M; ACCUMULATOR 2ND FRACTION INR L; TO ADDR ACCUM 3RD FRCTN MOV D,M; ACCUMULATOR 3RD FRCTN JMP ADD12; TO SET EXIT CONDITIONS ; FLOATING POINT LOAD ENTRY POINT. FLOAD: MOV A,M; OPERAND EXPONENT ANA A ; SET CONTROL BITS JZ FZERO; IF OPERAND IS ZERO MOV E,A; OPERAND EXPONENT INR L; TO ADDR OP SIGN AND 1ST MOV A,M; OPERAND SIGN AND 1ST FRCTN INR L; TO ADDRESS OPERAND 2ND FRACTION MOV C,M; OPERAND 2ND FRACTION INR L; TO ADDRESS OPERAND 3RD FRACTION MOV D,M; OPERAND 3RD FRACTION ; STORE THE OPERAND IN THE ACCUMULATOR. MOV L,A; OPERAND SIGN AND 1ST FRCTN FLOAD1: ORI 80H; ACCUMULATOR 1ST FRACTION MOV B,A; ACCUMULATOR 1ST FRACTION XRA L; ACCUMULATOR SIGN LXI H,ACCE; TO ADDR ACCUM EXPONENT CALL FSTR0; SET THE ACCUMULATOR XRA B; ACCUM SIGN AND 1ST FRCTN ; SET CONTROL BITS AND EXIT MOV B,A; ACCUM SIGN AND 1ST FRACTION ORI 1; SET SIGN BIT FOR EXIT MOV A,E; ACCUMULATOR EXPONENT RET ; RETURN TO CALLER ; FLOATING POINT MUL SUBROUTINE ENT. PNT. FMUL: MOV A,M; OPERAND EXPONENT ANA A ; SET CONTROL BITS CNZ MDEX; READ OPERAND IF NOT ZERO JZ FZERO; IF ZERO OR UNDERFLOW JC OVERF; IF OVERFLOW CALL MULX; CALL FIXED MULT SUBRTN ; NORMALIZE IF NECESSARY. MOV A,B; 1ST PRODUCT ANA A ; SET CONTROL BITS JM RNDA; IF NO NORMALIZATION REQUIRED LXI H,ACCE; TO ADDR ACCUM EXPONENT MOV A,M; ACCUMULATOR EXPONENT SBI 1; DECREMENT ACCUMULATOR EXPONENT MOV M,A; ACCUMULATOR EXPONENT RZ ; RETURN TO CALLER IF UNDERFLOW CALL LSH; CALL LEFT SHIFT SUBROUTINE ; ROUND IF NECESSARY. RNDA: CALL ROND; CALL ROUNDING SUBROUTINE JC OVERF; IF OVERFLOW MOV B,A; ACCUM SIGN AND 1ST FRACTION ORI 1; SET SIGN BIT MOV A,E; ACCUMULATOR EXPONENT RET ; RETURN TO CALLER ; FLOATING POINT DIV SUBROUTINE ENT. PNT. FDIV: XRA A; ZERO SUB M; COMPLEMENT OF DIVISOR EXPONENT CPI 1; SET CARRY IF DIVISION BY ZERO CNC MDEX; READ OPERAND IF NOT ZERO JC OVERF; IF OVERFLOW OR DIVISION BY ZERO JZ FZERO; IF UNDERFLOW OR ZERO MOV C,A; DIVISOR 1ST FRACTION CALL DIVX; CALL FIXED DIV SUBRTN JC RNDA; IF NO OVERFLOW ; SET OVERFLOW FLAG. OVERF: LXI H,OVER; TO ADDR OVERFLOW FLAG MVI A,0FFH; OVERFLOW FLAG MOV M,A; OVERFLOW FLAG RLC ; SET CARRY BIT FOR EXIT RET ; RETURN TO CALLER DB 0; CHECK SUM WORD ; FLOATING POINT SUB SUBROUTINE ENT. PNT. FSUB: MVI A,80H; MASK TO CHANGE OP SIGN DB 0EH; LBI INST TO SKIP NEXT WD ; FLOATING POINT ADD SUBROUTINE ENT. PNT. FADD: XRA A; ZERO ; LOAD THE OPERAND. MOV E,M; OPERAND EXPONENT INR L; TO ADDR OP SIGN, 1ST FRCTN XRA M; OPERAND SIGN AND 1ST FRCTN MOV B,A; OPERAND SIGN AND 1ST FRCTN INR L; TO ADDR OPERAND 2ND MOV C,M; OPERAND 2ND FRACTION INR L; TO ADDR OPERAND 3RD FRCTN MOV D,M; OPERAND 3RD FRACTION ; SAVE INITIAL EXPONENT. LXI H,ACCE; TO ADDR ACCUM EXPONENT MOV A,M; ACCUMULATOR EXPONENT DCR L; TO ADDR INITIAL EXPONENT MOV M,A; INITIAL EXPONENT ; CHECK FOR ZERO OPERAND. MOV A,E; OPERAND EXPONENT ANA A ; SET CONTROL BITS JZ FTEST; IF OPERAND IS ZERO ; GENERATE SUBTRACTION FLAG, RESTORE ; SUPPRESSED FRACTION BIT. MOV L,B; OPERAND SIGN AND 1ST FRCTN MOV A,B; OPERAND SIGN AND 1ST FRACTION ORI 80H; OPERAND 1ST FRACTION MOV B,A; OPERAND 1ST FRACTION XRA L; OPERAND SIGN MVI L,LOW(ACCS); TO ADDRESS ACCUMULATOR SIGN XRA M; SUBTRACTION FLAG MVI L,LOW(SF); TO ADDRESS SUBTRACTION FLAG MOV M,A; SUBTRACTION FLAG ; DETERMINE RELATIVE MAGNITUDES OF ; OPERAND AND ACCUMULATOR. MVI L,LOW(ACCE); TO ADDRESS ACCUMULATOR EXPONENT MOV A,M; ACCUMULATOR EXPONENT ANA A ; SET CONTROL BITS JZ ADD17; IF ACCUMULATOR IS ZERO SUB E; DIFFERENCE IN EXPONENTS JC ADD2; IF ACCUM SMALLER THAN OP ; CHECK FOR INSIGNIFICANT OPERAND. JM FTEST; IF THE OPERAND IS INSIGNIFICANT CPI 25; COMPARE SHIFT COUNT TO 25 JC ADD3; JOIN EXCH PATH IF OP SIGNIF JMP FTEST; OPERAND IS INSIGNIFICANT ; CHECK FOR INSIGNIFICANT ACCUMULATOR ADD2: JP ADD17; IF ACCUM IS INSIGNIFICANT CPI 0E7H; COMPARE SHIFT COUNT TO MINUS 25 JC ADD17; IF ACCUM IS INSIGNIFICANT MOV M,E; OPERAND EXPONENT MOV E,A; SHIFT COUNT LXI H,SF; TO ADDRESS THE SUBTRACTION FLAG MOV A,M; SUBTRACTION FLAG MVI L,LOW(ACCS); TO ADDRESS THE ACCUMULATOR SIGN XRA M; OPERAND SIGN MOV M,A; ACCUMULATOR SIGN XRA A; ZERO SUB E; COMPLEMENT SHIFT COUNT ; EXCHANGE ACCUMULATOR AND OPERAND. INR L; TO ADDR ACCUM 1ST FRACTION MOV E,M; ACCUMULATOR 1ST FRACTION MOV M,B; OPERAND 1ST FRACTION MOV B,E; ACCUMULATOR 1ST FRACTION INR L; TO ADDR ACCUM 2ND FRACTION MOV E,M; ACCUMULATOR 2ND FRACTION MOV M,C; OPERAND 2ND FRACTION MOV C,E; ACCUMULATOR 2ND FRACTION INR L; TO ADDR ACCUM 3RD FRACTION MOV E,M; ACCUMULATOR 3RD FRACTION MOV M,D; OPERAND 3RD FRACTION MOV D,E; ACCUMULATOR 3RD FRACTION ; POSITION THE OPERAND. ADD3: CALL RSH; POSITION THE OPERAND LXI H,SF; TO ADDRESS SUBTRACTION FLAG MOV A,M; SUBTRACTION FLAG ANA A ; SET CONTROL BITS MVI L,LOW(ACC3); TO ADDR ACCUM 3RD FRCTN JM ADD9; IF SUBTRACTION REQUIRED ; ADD ADDEND TO AUGEND. MOV A,M; AUGEND 3RD FRACTION ADD D; ADDEND 3RD FRACTION MOV D,A; SUM 3RD FRACTION DCR L; TO ADDRESS AUGEND 2ND FRACTION MOV A,M; AUGEND 2ND FRACTION ADC C; ADDEND 2ND FRACTION MOV C,A; SUM 2ND FRACTION DCR L; TO ADDRESS AUGEND 1ST FRACTION MOV A,M; AUGEND 1ST FRACTION ADC B; ADDEND 1ST FRACTION MOV B,A; SUM 1ST FRACTION JNC ADD11; IF NO CARRY FROM 1ST FRCTN ; RIGHT SHIFT SUM TO NORMALIZED POSITION. RAR ; RIGHT SHIFT SUM 1ST FRACTION MOV B,A; SUM 1ST FRACTION MOV A,C; SUM 2ND FRACTION RAR ; RIGHT SHIFT SUM 2ND FRACTION MOV C,A; SUM 2ND FRACTION MOV A,D; SUM 3RD FRACTION RAR ; RIGHT SHIFT SUM 3RD FRACTION MOV D,A; SUM 3RD FRACTION RAR ; 4TH FRCTN = LOW BIT OF 3RD MOV E,A; SUM 4TH FRACTION MVI L,LOW(ACCE); TO ADDRESS ACCUMULATOR EXPONENT MOV A,M; ACCUMULATOR EXPONENT ADI 1; INCREMENT ACCUMULATOR EXPONENT JC OVERF; IF OVERFLOW MOV M,A; ACCUMULATOR EXPONENT JMP ADD11; TO ROUND FRACTION ; SUBTRACT SUBTRAHEND FROM MINUEND. ADD9: XRA A; MINUEND 4TH FRCTN IS ZERO SUB E; SUBTRAHEND 4TH FRACTION MOV E,A; DIFFERENCE 4TH FRACTION MOV A,M; MINUEND 3RD FRACTION SBB D; SUBTRAHEND 3RD FRACTION MOV D,A; DIFFERENCE 3RD FRACTION DCR L; TO ADDRESS MINUEND 2ND FRACTION MOV A,M; MINUEND 2ND FRACTION SBB C; SUBTRAHEND 2ND FRACTION MOV C,A; DIFFERENCE 2ND FRACTION DCR L; TO ADDRESS MINUEND 1ST FRACTION MOV A,M; MINUEND 1ST FRACTION SBB B; SUBTRAHEND 1ST FRACTION MOV B,A; DIFFERENCE 1ST FRACTION ADD10: CC FCOMP; COMPLEMENT IF NEGATIVE CP NORM; NORMALIZE IF NECESSARY JP FZERO; IF UNDERFLOW OR ZERO ADD11: CALL ROND; CALL ROUNDING SUBROUTINE JC OVERF; IF OVERFLOW ADD12: MOV B,A; ACCUM SIGN AND 1ST FRCTN LXI H,PREX; TO ADDRESS PREV EXPONENT MOV A,E; ACCUMULATOR EXPONENT SUB M; DIFFERENCE IN EXPONENTS MOV L,A; DIFFERENCE IN EXPONENTS MOV A,B; ACCUM SIGN AND 1ST FRCTN ORI 1; SET SIGN BIT FOR EXIT MOV A,E; ACCUMULATOR EXPONENT MOV E,L; SIGNIFICANCE INDEX RET ; RETURN TO CALLER ; LOAD THE ACCUMULATOR WITH THE OPERAND. ADD17: LXI H,SF; TO ADDR SUBTRACTION FLAG MOV A,M; SUBTRACTION FLAG MVI L,LOW(ACCS); TO ADDR ACCUMULATOR SIGN XRA M; OPERAND SIGN DCR L; TO ADDR ACCUM EXPONENT CALL FSTR0; SET THE ACCUMULATOR XRA B; ACCUM SIGN AND 1ST FRCTN JMP ADD12; JOIN EXIT CODE DB 0; CHECK SUM WORD ; SUBROUTINE TO READ THE OPERAND AND ; CHECK THE ACCUMULATOR EXPONENT. MDEX: MOV B,A; EXPONENT MODIFIER INR L; TO ADDR OP SIGN, 1ST FRCTN MOV C,M; OPERAND SIGN AND 1ST FRACTION INR L; TO ADDRESS OPERAND 2ND FRACTION MOV D,M; OPERAND 2ND FRACTION INR L; TO ADDRESS OPERAND 3RD FRACTION MOV E,M; OPERAND 3RD FRACTION LXI H,ACCE; TO ADDRESS ACCUMULATOR EXPONENT MOV A,M; ACCUMULATOR EXPONENT ANA A ; SET CONTROL BITS RZ ; RETURN IF ACCUM IS ZERO ADD B; RESULT EXPONENT PLUS BIAS MOV B,A; RESULT EXPONENT PLUS BIAS RAR ; CARRY TO SIGN XRA B; CARRY AND SIGN MUST DIFFER MOV A,B; RESULT EXPONENT PLUS BIAS MVI B,80H; EXP BIAS, SIGN MASK, MS BIT JP OVUN; IF OVERFLOW OR UNDERFLOW SUB B; REMOVE EXCESS EXP BIAS RZ ; RETURN IF UNDERFLOW MOV M,A; RESULT EXPONENT INR L; TO ADDRESS ACCUMULATOR SIGN MOV A,M; ACCUMULATOR SIGN XRA C; RESULT SIGN IN SIGN BIT ANA B ; RESULT SIGN MOV M,A; RESULT SIGN MOV A,C; OPERAND SIGN AND 1ST FRCTN ORA B; OPERAND 1ST FRACTION RET ; RETURN TO CALLER OVUN: RLC ; SET CARRY BIT IF OVERFLOW RC ; RETURN IF OVERFLOW XRA A; ZERO RET ; RETURN IF UNDERFLOW ; SUBROUTINE TO LEFT SHIFT THE B, C, ; D, AND E REGISTERS ONE BIT. LSH: MOV A,E; ORIGINAL CONTENTS OF E RAL ; LEFT SHIFT E MOV E,A; RESTORE CONTENTS OF E REGISTER LSH1: MOV A,D; ORIGINAL CONTENTS OF D REGISTER RAL ; LEFT SHIFT D MOV D,A; RESTORE CONTENTS OF D REGISTER MOV A,C; ORIGINAL CONTENTS OF C REGISTER RAL ; LEFT SHIFT C MOV C,A; RESTORE CONTENTS OF C REGISTER MOV A,B; ORIGINAL CONTENTS OF B REGISTER ADC A; LEFT SHIFT B MOV B,A; RESTORE CONTENTS OF B REGISTER RET ; RETURN TO CALLER ; RIGHT SHIFT THE B, C, D AND E REGISTERS ; BY THE SHIFT COUNT IN THE A REGISTER ; SHIFT OPERAND TO REGISTER INDICATED BY ; SHIFT COUNT RSH: MVI E,0; OPERAND 4TH FRCTN IS ZERO RSH0: MVI L,8; EACH REG IS 8 BITS OF SHIFT RSH1: CMP L; COMPARE SHIFT COUNT TO 8 JM RSH2; IF REQ SHIFT LESS THAN 8 MOV E,D; OPERAND 4TH FRACTION MOV D,C; OPERAND 3RD FRACTION MOV C,B; OPERAND 2ND FRACTION MVI B,0; OPERAND 1ST FRACTION IS ZERO SUB L; REDUCE SHIFT COUNT BY 1 REG JNZ RSH1; IF MORE SHIFTS REQUIRED ; SHIFT OPERAND RIGHT BY -SHIFT COUNT- ; BITS. RSH2: ANA A ; SET CONTROL BITS RZ ; RETURN IF SHIFT COMPLETE MOV L,A; SHIFT COUNT RSH3: ANA A ; CLEAR CARRY BIT MOV A,B; OPERAND 1ST FRACTION RAR ; RIGHT SHIFT OP 1ST FRCTN MOV B,A; OPERAND 1ST FRACTION MOV A,C; OPERAND 2ND FRACTION RAR ; RIGHT SHIFT OP 2ND FRCTN MOV C,A; OPERAND 2ND FRACTION MOV A,D; OPERAND 3RD FRACTION RAR ; RIGHT SHIFT OP 3RD FRCTN MOV D,A; OPERAND 3RD FRACTION MOV A,E; OPERAND 4TH FRACTION RAR ; RIGHT SHIFT OP 4TH FRCTN MOV E,A; OPERAND 4TH FRACTION DCR L; DECREMENT SHIFT COUNT JNZ RSH3; IF MORE SHIFTS REQUIRED RET ; RETURN TO CALLER ; COMPLEMENT THE B, C, D, AND E REGISTERS. FCOMP: DCR L; TO ADDR ACCUM SIGN MOV A,M; ACCUMULATOR SIGN XRI 80H; CHANGE SIGN MOV M,A; ACCUMULATOR SIGN COMP1: XRA A; ZERO MOV L,A; ZERO SUB E; COMPLEMENT 4TH FRCTN MOV E,A; 4TH FRACTION MOV A,L; ZERO SBB D; COMPLEMENT 3RD FRCTN MOV D,A; 3RD FRACTION MOV A,L; ZERO SBB C; COMPLEMENT 2ND FRCTN MOV C,A; 2ND FRACTION MOV A,L; ZERO SBB B; COMPLEMENT 1ST FRCTN MOV B,A; 1ST FRACTION RET ; RETURN TO CALLER ; NORMALIZE THE REGISTERS. NORM: MVI L,20H; MAX NORMALIZING SHIFT NORM1: MOV A,B; 1ST FRACTION ANA A ; SET CONTROL BITS JNZ NORM3; IF 1ST FRACTION NONZERO MOV B,C; 1ST FRACTION MOV C,D; 2ND FRACTION MOV D,E; 3RD FRACTION MOV E,A; ZERO 4TH FRACTION MOV A,L; NORMALIZING SHIFT COUNT SUI 8; REDUCE SHIFT COUNT MOV L,A; NORMALIZING SHIFT COUNT JNZ NORM1; IF FRACTION NONZERO RET ; IF FRACTION IS ZERO NORM2: DCR L; DECREMENT SHIFT COUNT MOV A,E; ORIGINAL CONTENTS OF E RAL ; LEFT SHIFT E MOV E,A; RESTORE CONTENTS OF E REGISTER MOV A,D; ORIGINAL CONTENTS OF D REGISTER RAL ; LEFT SHIFT D MOV D,A; RESTORE CONTENTS OF D REGISTER MOV A,C; ORIGINAL CONTENTS OF C REGISTER RAL ; LEFT SHIFT C MOV C,A; RESTORE CONTENTS OF C REGISTER MOV A,B; ORIGINAL CONTENTS OF B REGISTER ADC A; LEFT SHIFT B MOV B,A; RESTORE CONTENTS OF B REGISTER NORM3: JP NORM2; IF NOT NORMALIZED MOV A,L; NORMALIZING SHIFT COUNT SUI 20H; REMOVE BIAS LXI H,ACCE; TO ADDR ACCUM EXPONENT ADD M; ADJUST ACCUM EXPONENT MOV M,A; NEW ACCUM EXPONENT RZ ; RETURN IF ZERO EXP RAR ; BORROW BIT TO SIGN ANA A ; SET SIGN TO IND. UNDERFLOW RET ; RETURN TO CALLER ; SUBROUTINE TO ROUND THE B, C, D REGISTERS. ROND: LXI H,ACCE; TO ADDR ACCUM EXPONENT MOV A,E; 4TH FRACTION ANA A ; SET CONTROL BITS MOV E,M; ACCUMULATOR EXPONENT CM RNDR; CALL 2ND LEVEL ROUNDER RC ; IF OVERFLOW MOV A,B; 1ST FRACTION INR L; TO ADDR ACCUM SIGN XRA M; ACCUM SIGN AND 1ST FRCTN JMP STR1; RETURN THRU STORE SUBR. ; SECOND LEVEL ROUNDING SUBROUTINE. RNDR: INR D; ROUND 3RD FRACTION RNZ ; RETURN IF NO CARRY INR C; CARRY TO 2ND FRACTION RNZ ; RETURN IF NO CARRY INR B; CARRY TO 1ST FRACTION RNZ ; RETURN IF NO CARRY MOV A,E; ACCUMULATOR EXPONENT ADI 1; INCREMENT ACCUM EXPONENT MOV E,A; NEW ACCUM EXPONENT MVI B,80H; NEW 1ST FRACTION MOV M,A; NEW ACCUM EXPONENT RET ; RETURN TO ROND SUBROUTINE ; FIXED POINT MULTIPLY SUBROUTINE. MULX: LXI H,MULP1+1; TO ADDR 1ST MULTIPLICAND MOV M,A; 1ST MULTIPLICAND LXI H,MULP2+1; TO ADDR 2ND MULTIPLICAND MOV M,D; 2ND MULTIPLICAND LXI H,MULP3+1; TO ADDR 3RD MULTIPLICAND MOV M,E; 3RD MULTIPLICAND XRA A; CLEAR 6TH PRODUCT MOV E,A; CLEAR 5TH PRODUCT MOV D,A; CLEAR 4TH PRODUCT ; MULTIPLY BY EACH ACCUMULATOR ; FRACTION IN TURN. LXI H,ACC3; TO ADDRESS 3RD FRCTN CALL MULX2; MULTIPLY BY ACCUM 3RD FRCTN MVI L,LOW(ACC2); TO ADDRESS 2ND FRCTN CALL MULX1; MULTIPLY BY ACCUM 2ND FRCTN MVI L,LOW(ACC1); TO ADDRESS 1ST FRCTN ; MULTIPLY BY ONE ACCUMULATOR WORD. MULX1: MOV A,D; 5TH PARTIAL PRODUCT MOV E,C; 4TH PARTIAL PRODUCT MOV D,B; 3RD PARTIAL PRODUCT MULX2: MOV B,M; MULTIPLIER MOV L,A; 5TH PARTIAL PRODUCT XRA A; ZERO MOV C,A; 2ND PARTIAL PRODUCT SUB B; SET CARRY BIT FOR EXIT FLAG JC MULX3; IF MULTIPLIER IS NOT ZERO MOV C,D; 2ND PARTIAL PRODUCT MOV D,E; 3RD PARTIAL PRODUCT RET ; MULT BY ZERO COMPLETE ; COMPLETE ADDITION OF MULTIPLICAND. MULX5: MOV C,A; 2ND PARTIAL PRODUCT JNC MULX3; IF NO CARRY TO 1ST PRODUCT INR B; ADD CARRY TO 1ST PRODUCT ANA A ; CLEAR CARRY BIT ; LOOP FOR EACH BIT OF MULTIPLIER WORD. MULX3: MOV A,L; 5TH PART PRODUCT, EXIT FLAG ADC A; SHIFT EXIT FLAG OUT IF DONE RZ ; EXIT IF MULTIPLICATION DONE MOV L,A; 5TH PART PRODUCT, EXIT FLAG MOV A,E; 4TH PARTIAL PRODUCT RAL ; SHIFT 4TH PARTIAL PRODUCT MOV E,A; 4TH PARTIAL PRODUCT MOV A,D; 3RD PARTIAL PRODUCT RAL ; SHIFT 3RD PARTIAL PRODUCT MOV D,A; 3RD PARTIAL PRODUCT MOV A,C; 2ND PARTIAL PRODUCT RAL ; SHIFT 2ND PARTIAL PRODUCT MOV C,A; 2ND PARTIAL PRODUCT MOV A,B; 1ST PART PROD AND MULTPLIER RAL ; SHIFT 1ST PROD AND MULTIPLIER MOV B,A; 1ST PART PROD AND MULTIPLIER JNC MULX3; IF NO ADDITION REQUIRED ; ADD THE MULTIPLICAND TO THE PRODUCT ; IF THE MULTIPLIER BIT IS ONE. MOV A,E; 4TH PARTIAL PRODUCT ; THE FOLLOWING CODE WAS MOVED FROM THE BEGINNING ; OF THE PROGRAM TO THIS LOCATION TO MAKE THINGS ; A LITTLE EASIER... MULX4: MULP3: ADI 0; ADD OPERAND 3RD FRACTION MOV E,A; 4TH PARTIAL PRODUCT MOV A,D; 3RD PARTIAL PRODUCT MULP2: ACI 0; ADD OPERAND 2ND FRACTION MOV D,A; 3RD PARTIAL PRODUCT MOV A,C; 2ND PARTIAL PRODUCT MULP1: ACI 0; ADD OPERAND 1ST FRACTION JMP MULX5 ; FIXED POINT DIVIDE SUBROUTINE. ; SUBTRACT DIVISOR FROM ACCUMULATOR TO ; OBTAIN 1ST REMAINDER. DIVX: LXI H,ACC3; TO ADDRESS ACCUM 3RD FRCTN MOV A,M; ACCUMULATOR 3RD FRACTION SUB E; DIVISOR 3RD FRACTION MOV M,A; REMAINDER 3RD FRACTION DCR L; TO ADDRESS ACCUM 2ND FRCTN MOV A,M; ACCUMULATOR 2ND FRACTION SBB D; DIVISOR 2ND FRACTION MOV M,A; REMAINDER 2ND FRACTION DCR L; TO ADDRESS ACCUM 1ST FRCTN MOV A,M; ACCUMULATOR 1ST FRACTION SBB C; DIVISOR 1ST FRACTION MOV M,A; REMAINDER 1ST FRACTION ; HALVE THE DIVISOR AND STORE FOR ; ADDITION OR SUBTRACTION. MOV A,C; DIVISOR 1ST FRACTION RAL ; SET CARRY BIT MOV A,C; DIVISOR 1ST FRACTION RAR ; HALF OF DIVISOR 1ST FRCTN ; + 80H TO CORRECT QUOTIENT LXI H,OP1S+1; TO ADDRESS 1ST SUBTRACT DIVISOR MOV M,A; 1ST SUBTRACT DIVISOR LXI H,OP1A+1; TO ADDRESS 1ST ADD DIVISOR MOV M,A; 1ST ADD DIVISOR MOV A,D; DIVISOR 2ND FRACTION RAR ; HALF OF DIVISOR 2ND FRACTION LXI H,OP2S+1; TO ADDRESS 2ND SUBTRACT DIVISOR MOV M,A; 2ND SUBTRACT DIVISOR LXI H,OP2A+1; TO ADDRESS 2ND ADD DIVISOR MOV M,A; 2ND ADD DIVISOR MOV A,E; DIVISOR 3RD FRACTION RAR ; HALF OF DIVISOR 3RD FRACTION LXI H,OP3S+1; TO ADDRESS 3RD SUBTRACT DIVISOR MOV M,A; 3RD SUBTRACT DIVISOR LXI H,OP3A+1; TO ADDRESS 3RD ADD DIVISOR MOV M,A; 3RD ADD DIVISOR MVI B,0; INIT QUOTIENT 1ST FRCTN MOV A,B; DIVISOR FOURTH FRACTION IS ZERO RAR ; LOW BIT OF DIVISOR 3RD FRACTION LXI H,OP4S+1; TO ADDRESS 4TH SUBTRACT DIVISOR MOV M,A; 4TH SUBTRACT DIVISOR LXI H,OP4A+1; TO ADDRESS 4TH ADD DIVISOR MOV M,A; 4TH ADD DIVISOR LXI H,OP4X+1; TO ADDRESS 4TH ADD DIVISOR MOV M,A; 4TH ADD DIVISOR ; LOAD 1ST REMAINDER, CHECK SIGN. LXI H,ACC1; TO ADDR REMAINDER 1ST FRCTN MOV A,M; REMAINDER 1ST FRACTION INR L; TO ADDR REMAINDER 2ND FRCTN MOV D,M; REMAINDER 2ND FRACTION INR L; TO ADDR REMAINDER 3RD FRCTN MOV E,M; REMAINDER 3RD FRACTION ANA A ; SET CONTROL BITS JM DIVX4; IF REMAINDER IS NEGATIVE ; ADJUST EXPONENT,POSITION REMAINDER ; AND INITIALIZE THE QUOTIENT. MVI L,LOW(ACCE); TO ADDRESS ACCUMULATOR EXPONENT MOV C,M; QUOTIENT EXPONENT INR C; INCREMENT QUOTIENT EXPONENT RZ ; RETURN IF OVERFLOW MOV M,C; QUOTIENT EXPONENT MOV L,E; REMAINDER 3RD FRACTION MOV H,D; REMAINDER 2ND FRACTION MOV E,A; REMAINDER 1ST FRACTION MVI D,1; INITIALIZE QUOT 3RD FRCTN MOV C,B; INITIALIZE QUOT 2ND FRCTN ; SUBTRACT THE DIVISOR FROM THE REMAINDER ; IF IT IS POSITIVE DIVX1: XRA A; REMAINDER 4TH FRCTN IS ZERO CALL DIVX5; DIVX2: RLC ; SHFT REM 4TH FRCTN TO CY ; SHIFT THE REMAINDER LEFT ONE BIT. MOV A,B; QUOTIENT 1ST FRACTION RAL ; MS BIT OF QUOTIENT TO CY RC ; IF DIVISION COMPLETE RAR ; REMAINDER 4TH FRCTN TO CY MOV A,L; REMAINDER 3RD FRACTION RAL ; LEFT SHIFT REM 3RD FRCTN MOV L,A; REMAINDER 3RD FRACTION MOV A,H; REMAINDER 2ND FRACTION RAL ; LEFT SHIFT REM 2ND FRCTN MOV H,A; REMAINDER 2ND FRACTION CALL LSH; CALL LEFT SHIFT SUBROUTINE ; BRANCH IF SUBTRACTION IS REQUIRED MOV A,D; QUOTIENT 3RD FRACTION RRC ; REM SIGN INDIC TO CARRY BIT JC DIVX1; TO SUB DIVISOR IF REM POS ; ADD THE DIVISOR IF THE REMAINDER ; IS NEGATIVE. DIVX3: MOV A,L; REMAINDER 3RD FRACTION JMP DIVX6; ; POSITION THE REMAINDER AND INITIALIZE ; THE QUOTIENT. DIVX4: MOV L,E; REMAINDER 3RD FRACTION MOV H,D; REMAINDER 2ND FRACTION MOV E,A; REMAINDER 1ST FRACTION MOV D,B; INITIALIZE QUOT 3RD FRCTN MOV C,B; INITIALIZE QUOT 2ND FRCTN JMP DIVX3; ADD DIVISOR IF REM IS NEG ; ORIGINALLY, THIS CODE WAS AT THE BEGINNING ; OF THE PROGRAM... DIVX5: OP4S: SUI 0; SUB DIVISOR 4TH FRACTION MOV A,L; REM 3RD FRACTION OP3S: SBI 0; SUB DIVISOR 3RD FRACTION MOV L,A; REM 3RD FRACTION MOV A,H; REM 2ND FRACTION OP2S: SBI 0; SUB DIVISOR 2ND FRACTION MOV H,A; REM 2ND FRACTION MOV A,E; REM 1ST FRACTION OP1S: SBI 0; SUB DIVISOR 1ST FRACTION MOV E,A; REM 1ST FRACTION OP4A: MVI A,0; REM 4TH FRACTION RET DIVX6: OP3A: ADI 0; ADD DIVISOR 3RD FRACTION MOV L,A; REM 3RD FRACTION MOV A,H; REM 2ND FRACTION OP2A: ACI 0; ADD DIVISOR 2ND FRACTION MOV H,A; REM 2ND FRACTION MOV A,E; REM 1ST FRACTION OP1A: ACI 0; ADD DIVISOR 1ST FRACTION MOV E,A; REM 1ST FRACTION OP4X: MVI A,0; REM 4TH FRACTION JMP DIVX2 END