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Assembly Source File | 1995-03-29 | 33.6 KB | 1,680 lines

.386 _TEXT SEGMENT BYTE PUBLIC USE32 'CODE' ASSUME cs:_TEXT extern _rand_table:dword extern _sin_table:word extern _asin_table:word extern _tan_table1:dword extern _tan_table3:dword extern _tan_table4:dword extern _atan_table1:word extern _atan_table2:word extern _atan_table3:word extern _atan_table4:word extern _log2_table:word extern _exp2_table:word extern _sqrt_table:word public _rnd1 public _rnd2 public _rnd3 _rnd1 dd 193 _rnd2 dd 0 _rnd3 dd 122231 public rand32_ rand32_ proc near push edx mov edx,[_rnd3] mov eax,[_rnd1] and edx,03FFh mul edx inc [_rnd2] mov edx,[_rnd2] and edx,16383 jne r_a push edx shr edx,14 add [_rnd3],3 and edx,16383 add eax,[_rand_table+edx] add [_rand_table+edx],1239876 pop edx r_a: add eax,[_rand_table+edx] pop edx mov [_rnd1],eax ret rand32_ endp ; eax - desired two pow interval ; edx - desired interval public randpowint_ randpowint_ proc near push ebx mov ebx,eax get_another: ; unrolling starts push edx mov edx,[_rnd3] mov eax,[_rnd1] and edx,03FFh mul edx inc [_rnd2] mov edx,[_rnd2] and edx,16383 jne pir_a push edx shr edx,14 add [_rnd3],3 and edx,16383 add eax,[_rand_table+edx] add [_rand_table+edx],1239876 pop edx pir_a: add eax,[_rand_table+edx] pop edx mov [_rnd1],eax ; unrolling stops and eax,ebx cmp eax,edx jae get_another pop ebx ret randpowint_ endp public randinter_ randinter_ proc near push edx push ecx push eax frl00: xor ecx,ecx cmp eax,010000h jb frl0 shr eax,16 add cl,16 frl0: cmp eax,0100h jb frl1 shr eax,8 add cl,8 frl1: cmp eax,010h jb frl2 shr eax,4 add cl,4 frl2: cmp eax,04h jb frl3 shr eax,2 add cl,2 frl3: cmp eax,2 jb frl4 inc ecx frl4: inc cl mov edx,1 shl edx,cl pop ecx dec edx ; eax now holding 2pow interval gget_another: ; unrolling starts push edx mov edx,[_rnd3] mov eax,[_rnd1] and edx,03FFh mul edx inc [_rnd2] mov edx,[_rnd2] and edx,16383 jne ir_a push edx shr edx,14 add [_rnd3],3 and edx,16383 add eax,[_rand_table+edx] add [_rand_table+edx],1239876 pop edx ir_a: add eax,[_rand_table+edx] pop edx mov [_rnd1],eax ; unrolling stops and eax,edx cmp eax,ecx jae gget_another pop ecx pop edx ret randinter_ endp public ffsmul_ ; eax - contains fixfloat 1 ; edx - contains fixfloat 2 ; routine affects edx due to 64 bit multiplication ffsmul_ proc near imul edx shrd eax,edx,16 ret ffsmul_ endp public ffsdiv_ ; eax contains denominator (Above division line) ; edx contains nominator (Below division line) ffsdiv_ proc near push edx push ecx push ebx or eax,eax mov ecx,edx mov bl,0 jns fsd_1 neg eax inc bl fsd_1: or ecx,ecx mov edx,eax jns fsd_2 neg ecx inc bl fsd_2: shr edx,16 shl eax,16 cmp edx,ecx jae div_by_0 div ecx test bl,1 pop ebx pop ecx pop edx je fsd_3 neg eax fsd_3: ret div_by_0: test bl,1 pop ebx pop ecx pop edx jne dbz1 mov eax,07FFFFFFFh ret dbz1: mov eax,080000000h ret ffsdiv_ endp public ffmul_ ; eax - contains fixfloat 1 ; edx - contains fixfloat 2 ; routine affects edx due to 64 bit multiplication ffmul_ proc near mul edx shrd eax,edx,16 ret ffmul_ endp public ffdiv_ ; eax contains denominator (Above division line) ; edx contains nominator (Below division line) ffdiv_ proc near push edx push ecx mov ecx,edx mov edx,eax shl eax,16 shr edx,16 cmp edx,ecx jae div_by_00 div ecx pop ecx pop edx ret div_by_00: pop ecx pop edx mov eax,0FFFFFFFFh ret ffdiv_ endp public ffsin_ public ffcos_ ffcos_: add eax,04000h ; that's all there is to it ! ffsin_ proc near push ebx test eax,08000h setne bl and eax,07FFFh cmp eax,04000h jb fsn1 xor eax,07FFFh fsn1: shr eax,2 ; increased resolution 4 times mov ax,[_sin_table+eax*2] or bl,bl je ffsn2 neg eax ffsn2: pop ebx ret ffsin_ endp public ffasin_ ffasin_ proc near push ebx or eax,eax mov bl,0 jns fasn2 neg eax inc ebx fasn2: and eax,0FFFFh shr eax,4 mov ax,[_asin_table+eax*2] or bl,bl je fasn1 neg eax fasn1: pop ebx ret ffasin_ endp public ffacos_ ffacos_ proc near push ebx or eax,eax mov bl,0 jns facn2 neg eax inc ebx facn2: and eax,0FFFFh shr eax,4 mov ax,[_asin_table+eax*2] or bl,bl je facn1 neg eax facn1: pop ebx sub eax,04000h neg eax ret ffacos_ endp public fftan_ fftan_ proc near push ebx test eax,4000h mov bl,0 je ftn1 test eax,3FFFh jne ftn01 mov eax,030000000h ; almost infinity pop ebx ret ftn01: neg eax inc bl ftn1: and eax,03FFFh cmp eax,03C00h jae ftn3 shr eax,4 ; lowest tan interval or bl,bl mov eax,[_tan_table1+eax*4] je ftn11 neg eax ftn11: pop ebx ret ftn3: cmp eax,03F00h jae ftn4 and eax,03fch or bl,bl mov eax,[_tan_table3+eax] je ftn31 neg eax ftn31: pop ebx ret ftn4: and eax,0FFh or bl,bl mov eax,[_tan_table4+eax*4] je ftn41 neg eax ftn41: pop ebx ret fftan_ endp public ffatan_ ffatan_ proc near push ebx or eax,eax mov bl,0 jns fat0 neg eax inc ebx fat0: cmp eax,040000h jae fat1 shr eax,8 or bl,bl mov ax,[_atan_table1+eax*2] je fat01 neg eax fat01: pop ebx ret fat1: cmp eax,0100000h jae fat2 shr eax,12 or bl,bl mov ax,[_atan_table2+eax*2] je fat11 neg eax fat11: pop ebx ret fat2: cmp eax,02000000h ; 512.0 jae fat3 shr eax,17 or bl,bl mov ax,[_atan_table3+eax*2] je fat21 neg eax fat21: pop ebx ret fat3: cmp eax,020000000h ; 8192.0 jae fat4 shr eax,21 or bl,bl mov ax,[_atan_table4+eax*2] je fat31 neg eax fat31: pop ebx ret fat4: or bl,bl mov eax,03FFFh ; almost 90 degrees jns fat31 neg eax jmp fat31 ffatan_ endp public fflog2_ fflog2_ proc near push ecx push ebx or eax,eax mov ebx,eax jne ffl00 mov eax,80000000h ; approx -infinity pop ebx pop ecx ret ffl00: xor ecx,ecx cmp eax,010000h jb ffl0 shr eax,16 add cl,16 ffl0: cmp eax,0100h jb ffl1 shr eax,8 add cl,8 ffl1: cmp eax,010h jb ffl2 shr eax,4 add cl,4 ffl2: cmp eax,04h jb ffl3 shr eax,2 add cl,2 ffl3: cmp eax,2 jb ffl4 inc ecx ffl4: mov eax,ebx mov bl,cl sub cl,12 js ffl5 shr eax,cl jmp ffl6 ffl5: neg cl shl eax,cl ffl6: sub eax,01000h sub bl,16 mov cx,[_log2_table+eax*2] movsx eax,bl pop ebx shl eax,16 mov ax,cx pop ecx ret fflog2_ endp public ffexp2_ ffexp2_ proc near ; test eax,0FFFFh push ecx mov ecx,eax ; je fenodec shr eax,4 sar ecx,16 js fe1 and eax,0FFFh mov ax,[_exp2_table+eax*2] add eax,10000h shl eax,cl pop ecx ret fe1: and eax,0FFFh neg cl mov ax,[_exp2_table+eax*2] add eax,10000h shr eax,cl pop ecx ret fenodec: sar ecx,16 mov eax,1 add ecx,16 shl eax,cl pop ecx ret ffexp2_ endp public ffpow_ ffpow_ proc near ; neat procedure eh? call fflog2_ call ffsmul_ call ffexp2_ ret ffpow_ endp public ffsqrt_ ffsqrt_ proc near push ecx push ebx or eax,eax mov ebx,eax jne ffs00 mov eax,0h ; sqrt 0 = 0 pop ebx pop ecx ret ffs00: xor ecx,ecx cmp eax,010000h jb ffs0 shr eax,16 add cl,16 ffs0: cmp eax,0100h jb ffs1 shr eax,8 add cl,8 ffs1: cmp eax,010h jb ffs2 shr eax,4 add cl,4 ffs2: cmp eax,04h jb ffs3 shr eax,2 add cl,2 ffs3: cmp eax,2 jb ffs4 inc ecx ffs4: mov eax,ebx sub cl,15 test cl,1 je ffs5 inc cl ffs5: mov bl,cl add cl,4 jns ffs6 neg cl shl eax,cl jmp ffs7 ffs6: shr eax,cl ffs7: sar bl,1 mov ax,[_sqrt_table+eax*2] or bl,bl mov cl,bl js ffs8 shl eax,cl pop ebx pop ecx ret ffs8: neg cl pop ebx shr eax,cl pop ecx ret ffsqrt_ endp public fftrihyp_ fftrihyp_ proc near push ecx push ebx fthp0: mov ebx,edx ; 2 imul eax ; edx:eax - a mov ecx,edx fthp1: xchg eax,ebx ; ecx:ebx - a imul eax add ebx,eax ; 2 2 pop eax adc ecx,edx ; edx:eax - a +b push eax fthp11: imul eax add eax,ebx adc edx,ecx je t_hi_reg_zero ; bsr ecx,edx ; code from here push edx xor ecx,ecx cmp edx,010000h jb bsr00 shr edx,16 add cl,16 bsr00: cmp edx,0100h jb bsr01 shr edx,8 add cl,8 bsr01: cmp edx,010h jb bsr02 shr edx,4 add cl,4 bsr02: cmp edx,04h jb bsr03 shr edx,2 add cl,2 bsr03: cmp edx,2 jb bsr04 inc ecx bsr04: pop edx ; to here replaces bsr with a factor 2.5 speed gain add cl,17 test cl,1 je fthp2 inc ecx fthp2: mov ebx,ecx cmp cl,020h jae fthp20 shrd eax,edx,cl jmp t_ready_to_root fthp20: sub cl,020h mov eax,edx ; 20 shifts shr eax,cl jmp t_ready_to_root t_hi_reg_zero: ; bsr ecx,eax ; code from here push eax xor ecx,ecx cmp eax,010000h jb bsr10 shr eax,16 add cl,16 bsr10: cmp eax,0100h jb bsr11 shr eax,8 add cl,8 bsr11: cmp eax,010h jb bsr12 shr eax,4 add cl,4 bsr12: cmp eax,04h jb bsr13 shr eax,2 add cl,2 bsr13: cmp eax,2 jb bsr14 inc ecx bsr14: pop eax ; to here replaces bsr with a factor 2.5 speed gain sub cl,15 test cl,1 je thrz1 inc ecx thrz1: mov ebx,ecx or ecx,ecx js thrz2 shr eax,cl jmp t_ready_to_root thrz2: neg ecx shl eax,cl t_ready_to_root: shr eax,4 ; mov ecx,ebx and eax,0fffh sub cl,16 mov ax,[_sqrt_table+eax*2] sar cl,1 js trtr1 shl eax,cl pop ebx pop ecx ret trtr1: neg cl shr eax,cl pop ebx pop ecx ret fftrihyp_ endp public ffhyp_ ffhyp_ proc near push ecx push ebx fhp0: mov ebx,edx ; 2 imul eax ; edx:eax - a mov ecx,edx ; 2 fhp1: xchg eax,ebx ; ecx:ebx - a imul eax add eax,ebx ; 2 2 adc edx,ecx ; edx:eax - a + b je hi_reg_zero ; bsr ecx,edx ; code from here push edx xor ecx,ecx cmp edx,010000h jb bsr20 shr edx,16 add cl,16 bsr20: cmp edx,0100h jb bsr21 shr edx,8 add cl,8 bsr21: cmp edx,010h jb bsr22 shr edx,4 add cl,4 bsr22: cmp edx,04h jb bsr23 shr edx,2 add cl,2 bsr23: cmp edx,2 jb bsr24 inc ecx bsr24: pop edx ; to here replaces bsr with a factor 2.5 speed gain add cl,17 test cl,1 je fhp2 inc ecx fhp2: mov ebx,ecx cmp cl,020h jae fhp20 shrd eax,edx,cl jmp ready_to_root fhp20: sub cl,020h mov eax,edx ; 020h shifts shr eax,cl jmp ready_to_root hi_reg_zero: ; bsr ecx,eax ; code from here push eax xor ecx,ecx cmp eax,010000h jb bsr30 shr eax,16 add cl,16 bsr30: cmp eax,0100h jb bsr31 shr eax,8 add cl,8 bsr31: cmp eax,010h jb bsr32 shr eax,4 add cl,4 bsr32: cmp eax,04h jb bsr33 shr eax,2 add cl,2 bsr33: cmp eax,2 jb bsr34 inc ecx bsr34: pop eax ; to here replaces bsr with a factor 2.5 speed gain sub cl,15 test cl,1 je hrz1 inc ecx hrz1: mov ebx,ecx or ecx,ecx js hrz2 shr eax,cl jmp ready_to_root hrz2: neg ecx shl eax,cl ready_to_root: shr eax,4 ; mov ecx,ebx and eax,0fffh sub cl,16 mov ax,[_sqrt_table+eax*2] sar cl,1 js rtr1 shl eax,cl pop ebx pop ecx ret rtr1: neg cl shr eax,cl pop ebx pop ecx ret ffhyp_ endp public ffalmosthyp_ ffalmosthyp_ proc near or eax,eax push edx jns fah_1 neg eax fah_1: or edx,edx jns fah_2 neg edx fah_2: cmp eax,edx jae fah_3 xchg eax,edx fah_3: shr edx,1 add eax,edx pop edx ret ffalmosthyp_ endp public ffmuldiv_ ffmuldiv_ proc near push esi push ebx push ecx push eax push edx ffmd5: mov eax,ebx imul ecx je ffmd_zero_nominator mov ebx,eax mov ecx,edx mov eax,[esp] mov edx,[esp+4] imul edx or edx,edx mov esi,edx ; sign of nominator jns ffmd51 neg eax ; negating denominator neg edx ffmd51: or ecx,ecx jns ffmd52 xor esi,0x80000000 ; change sign of result not ebx not ecx ffmd52: cmp edx,0xFFFF ja ffmd520 shld edx,eax,16 shl eax,16 or ecx,ecx jmp ffmd521 ffmd520: shrd ebx,ecx,16 shr ecx,16 ffmd521: jne ffmd_more_shift cmp edx,ebx jae ffmd_overflow idiv ebx ; there is no test for overflow or esi,esi pop edx ; in this division jns ffmd53 neg eax ffmd53: add esp,4 pop ecx pop ebx pop esi ret ffmd_more_shift: shrd eax,edx,16 shr edx,16 shrd ebx,ecx,16 cmp edx,ebx jae ffmd_overflow idiv ebx or esi,esi pop edx jns ffmd54 neg eax ffmd54: add esp,4 pop ecx pop ebx pop esi ret ffmd_overflow: pop edx add esp,4 or esi,esi js ffmd6 mov eax,07FFFFFFFh pop ecx pop ebx pop esi ret ffmd_zero_nominator: pop edx pop eax xor eax,edx js ffmd6 mov eax,07FFFFFFFh ; positive infinity pop ecx pop ebx pop esi ret ffmd6: mov eax,080000000h ; negative infinity pop ecx pop ebx pop esi ret ffmuldiv_ endp public ffmmd_ ffmmd_ proc near push esi push ebx xor esi,esi push edx ffmmd2: imul edx jns ffmmd3 neg edx neg eax inc esi ffmmd3: or ebx,ebx jns ffmmd4 neg ebx dec esi ffmmd4: cmp edx,ebx jae ffmmd_overflow div ebx or esi,esi pop edx je ffmmd5 neg eax ffmmd5: pop ebx pop esi ret ffmmd_overflow: or esi,esi pop edx pop ebx pop esi js ffmmd6 mov eax,07FFFFFFFh ret ffmmd6: mov eax,080000000h ret ffmmd_ endp public ffortproj_ ; eax - a ; edx - b ; ebx - c ; ecx - d ; returns (a*b+c*d)/(a*a+c*c) ffortproj_ proc near push ebx push edx push ecx sar eax,5 sar edx,5 sar ebx,5 sar ecx,5 push eax call ffsmul_ ; eax = a*b push eax mov eax,ebx mov edx,ecx call ffsmul_ ; eax = c*d pop ecx ; ecx = a*b add ecx,eax ; ecx = a*b + c*d mov eax,ebx mov edx,ebx call ffsmul_ mov ebx,eax ; ebx = c*c pop eax mov edx,eax call ffsmul_ ; eax = a*a add ebx,eax ; ebx = c*c + a*a mov eax,ecx mov edx,ebx call ffsdiv_ pop ecx pop edx pop ebx ret ffortproj_ endp public ffortproj1_ ; eax - a ; edx - b ; ebx - c ; ecx - d ; returns (a*b+c*d)/sqrt(a*a+c*c) ffortproj1_ proc near push ebx push edx push ecx sar eax,6 sar edx,6 sar ebx,6 sar ecx,6 push eax call ffsmul_ ; eax = a*b push eax mov eax,ebx mov edx,ecx call ffsmul_ ; eax = c*d pop ecx ; ecx = a*b add ecx,eax ; ecx = a*b + c*d mov eax,ebx mov edx,ebx call ffsmul_ mov ebx,eax ; ebx = c*c pop eax mov edx,eax call ffsmul_ ; eax = a*a add eax,ebx ; ebx = c*c + a*a call ffsqrt_ ; root it mov edx,eax mov eax,ecx call ffsdiv_ shl eax,6 ; compensating root pop ecx pop edx pop ebx ret ffortproj1_ endp public ffdot_through_hyps_ ; eax - a ; edx - b ; ebx - c ; ecx - d ; returns (a*b+c*d)/(sqrt(a*a+c*c)*sqrt(b*b+d*d)) ffdot_through_hyps_ proc near push ebx push edx push ecx sar eax,5 sar edx,5 sar ebx,5 sar ecx,5 push edx push ecx push eax call ffsmul_ ; eax = a*b push eax mov eax,ebx mov edx,ecx call ffsmul_ ; eax = c*d pop ecx ; ecx = a*b add ecx,eax ; ecx = a*b + c*d mov eax,ebx mov edx,ebx call ffsmul_ mov ebx,eax ; ebx = c*c pop eax mov edx,eax call ffsmul_ ; eax = a*a add eax,ebx call ffsqrt_ mov ebx,eax ; ebx = sqrt(c*c + a*a) pop eax mov edx,eax call ffsmul_ ; eax = d*d pop edx push eax mov eax,edx call ffsmul_ ; eax = b*b pop edx add eax,edx call ffsqrt_ ; eax = sqrt(d*d + b*b) mov edx,ebx call ffmul_ ; eax = sqrt(d*d + b*b) * sqrt(c*c + a*a) mov edx,eax mov eax,ecx call ffsdiv_ ; eax = a*b + c*d / (sqrt(d*d + b*b) * sqrt(c*c + a*a)) pop ecx pop edx pop ebx ret ffdot_through_hyps_ endp public isqrt_ isqrt_ proc near push ecx push edx push eax ; bsr ecx,eax ; unfold ; code from here xor ecx,ecx cmp eax,010000h jb is30 shr eax,16 add cl,16 is30: cmp eax,0100h jb is31 shr eax,8 add cl,8 is31: cmp eax,010h jb is32 shr eax,4 add cl,4 is32: cmp eax,04h jb is33 shr eax,2 add cl,2 is33: cmp eax,2 jb is34 inc ecx is34: ; to here replaces bsr with a factor 2.5 speed gain mov edx,ecx sub cl,10 neg edx test cl,1 pop eax je is1 inc edx dec ecx is1: add dl,31 or cl,cl js is2 shr eax,cl jmp is3 is2: neg cl shl eax,cl is3: shr dl,1 mov ax,[_sqrt_table+eax*2] mov ecx,edx pop edx shr eax,cl pop ecx ret isqrt_ endp ; eax - denominator lo part ; edx - denominator hi ; ebx - nominator ; ecx - pointer to DWORD location to store ; decimal fraction of result. ; returns the integer part of result ; works with signed 64 bit quantities ; this routine does not check for any zero divisions public ff_double_div_ ff_double_div_ proc near push edx push edi xor edi,edi or edx,edx jns dd_1 neg edx neg eax ; make both numbers positive sbb edx,0 inc edi dd_1: or ebx,ebx jns dd_2 neg ebx inc edi dd_2: div ebx push eax ; this is integer part of ; division xor eax,eax ; produce decimal part of div ebx ; division pop edx ; eax - decpart, edx - intpart dd_4: test edi,1 je dd_5 neg edx ; negate integer part neg eax ; negate decimal part sbb edx,0 ; dec if non zero eax dd_5: mov [ecx],eax ; store away decimal fraction mov eax,edx ; return integer fraction dd_restore_reg: pop edi ; restore registers pop edx ret ff_double_div_ endp ; ; eax - pointer to low value ; edx - pointer to hi value ; ebx - 0 - ordinary shift ; no 0 - arithmetic shift ; ecx - nr of steps to shift, ; right is positive, ; left is negative ; public ff_double_shift_ ff_double_shift_ proc near push esi or ecx,ecx js dr_left ; rotate right mov esi,[edx] shrd [eax],esi,cl xor esi,esi or ebx,ebx jne dr_aritm shrd [edx],esi,cl pop esi ret dr_aritm: mov esi,[edx] sar esi,31 shrd [edx],esi,cl pop esi ret ; shift left dr_left: push ecx neg ecx mov esi,[eax] shld [edx],esi,cl xor esi,esi shld [eax],esi,cl pop ecx pop esi ret ff_double_shift_ endp ; /\ Y ; | ; This routine takes a | o (1,2) ; vector in it's rectangular form | / ; and returns the angle it forms | /\ V = atan(2/1) ; in relation to the point (1,0). |/ | ; that is coordinate (0,1) will return -------------> X ; (90/360)*65536 , ; coordinate (0,-1) will return ; ((-90/360)*65536) & 65535 ; ; renember, there are 65536 degrees in ; a circle in fixfloat universe. ; eax - x component ; edx - y component ; returns result in eax public ff_vec_to_ang_ ff_vec_to_ang_ proc near or eax,eax push edx push ecx mov cl,0 js ff_fta0 jne ff_fta1 or edx,edx je ff_zero_vector jmp ff_fta1 ff_fta0: neg eax ; make sure x component is positive neg edx inc cl ; flag that we have to subtract/add '180' degrees to angle ff_fta1: cmp edx,eax ; test if y>x jge ff_y_bigger push edx neg edx cmp edx,eax ; test if -y>x pop edx jge ff_y_bigger ; abs(x)>abs(y) xchg eax,edx ; put y on top in divisor, x in bottom call ffsdiv_ ; divide call ffatan_ ; arc tan jmp ff_fta2 ff_y_bigger: ; abs(y)>abs(x) push 0004000h or edx,edx jns ff_yb1 mov DWORD PTR[esp],000c000h ff_yb1: call ffsdiv_ call ffatan_ neg eax pop edx add eax,edx ff_fta2: or cl,cl ; see if need to flip angle '180' degrees pop ecx je ff_fta3 xor eax,08000h ; flip it ff_fta3: and eax,0FFFFh pop edx ret ff_zero_vector: xor eax,eax pop ecx pop edx ret ff_vec_to_ang_ endp ; ; this routine solves a 2:nd degree equation ; by std formula, for given p & 1 : ; ; 2 ; x + px + q = 0 ; ; setup at call : ; eax - p ; edx - q ; ebx - pointer to where to put conjugate part ( the +/- term ) ; ecx - pointer to where to put prefix part (-p/2) ; ; returns eax - 0 if solved OK ; returns eax - no 0 if no real roots ; ; routine handles cases where p*p/4-q>32767 correctly, ; since it uses intermediate 64 bit representation ; public ff_solve_2nd_poly_ ff_solve_2nd_poly_ proc near push edx push ecx push eax mov ecx,edx ; square the p term mov edx,eax imul edx shrd eax,edx,18 ; work with 64 bits for a while sar edx,18 or ecx,ecx ; slightly different behaviour if negative q value js ff2nd_1 sub eax,ecx sbb edx,0 jmp ff2nd_2 ff2nd_1: neg ecx add eax,ecx adc edx,0 ff2nd_2: js ff2nd_no_real_roots ; such things happens... xor ecx,ecx or edx,edx je ff2nd_4 ff2nd_3: shrd eax,edx,2 ; enable momentary overflow but still give correct result inc ecx ; with the help of afew shifts shr edx,2 jne ff2nd_3 ff2nd_4: call ffsqrt_ shl eax,cl mov [ebx],eax ; storing conjugate pop eax pop ecx neg eax ; calc -p/2 pop edx sar eax,1 mov [ecx],eax xor eax,eax ; indicate we did OK ret ff2nd_no_real_roots: pop eax pop ecx neg eax pop edx sar eax,1 mov [ecx],eax mov al,1 ; indicate no real roots ret ff_solve_2nd_poly_ endp _TEXT ENDS END