WebSVN – Kolibri OS – Blame – /programs/emulator/PrMK/trunk/MASMFpuLib.asm

Rev	Author	Line No.	Line
1863	yogev_ezra	1	;FpuAtoFL PROTO :DWORD,:DWORD,:DWORD
		2	;FpuFLtoA PROTO :DWORD,:DWORD,:DWORD,:DWORD
		3
		4	;FpuAdd PROTO :DWORD,:DWORD,:DWORD,:DWORD
		5	;FpuSub PROTO :DWORD,:DWORD,:DWORD,:DWORD
		6	;FpuMul PROTO :DWORD,:DWORD,:DWORD,:DWORD
		7	;FpuDiv PROTO :DWORD,:DWORD,:DWORD,:DWORD
		8	;FpuSqrt PROTO :DWORD,:DWORD,:DWORD
		9	;FpuXexpY PROTO :DWORD,:DWORD,:DWORD,:DWORD
		10	;FpuAbs PROTO :DWORD,:DWORD,:DWORD
		11	;FpuTrunc PROTO :DWORD,:DWORD,:DWORD
		12	;FpuRound PROTO :DWORD,:DWORD,:DWORD
		13	;FpuChs PROTO :DWORD,:DWORD,:DWORD
		14
		15	;FpuLnx PROTO :DWORD,:DWORD,:DWORD
		16	;FpuLogx PROTO :DWORD,:DWORD,:DWORD
		17	;FpuEexpX PROTO :DWORD,:DWORD,:DWORD
		18	;FpuTexpX PROTO :DWORD,:DWORD,:DWORD
		19
		20	;FpuSin PROTO :DWORD,:DWORD,:DWORD
		21	;FpuCos PROTO :DWORD,:DWORD,:DWORD
		22	;FpuTan PROTO :DWORD,:DWORD,:DWORD
		23	;FpuArcsin PROTO :DWORD,:DWORD,:DWORD
		24	;FpuArccos PROTO :DWORD,:DWORD,:DWORD
		25	;FpuArctan PROTO :DWORD,:DWORD,:DWORD
		26
		27	;FpuSinh PROTO :DWORD,:DWORD,:DWORD
		28	;FpuCosh PROTO :DWORD,:DWORD,:DWORD
		29	;FpuTanh PROTO :DWORD,:DWORD,:DWORD
		30	;FpuArcsinh PROTO :DWORD,:DWORD,:DWORD
		31	;FpuArccosh PROTO :DWORD,:DWORD,:DWORD
		32	;FpuArctanh PROTO :DWORD,:DWORD,:DWORD
		33
		34	;FpuSize PROTO :DWORD,:DWORD,:DWORD
		35	;FpuComp PROTO :DWORD,:DWORD,:DWORD
		36	;FpuExam PROTO :DWORD,:DWORD
		37	;FpuState PROTO :DWORD
		38
		39	SRC1_FPU EQU 1
		40	SRC1_REAL EQU 2
		41	SRC1_DMEM EQU 4
		42	SRC1_DIMM EQU 8
		43	SRC1_CONST EQU 16
		44
		45	ANG_DEG EQU 0
		46	ANG_RAD EQU 32
		47
		48	DEST_MEM EQU 0
		49	DEST_IMEM EQU 64
		50	DEST_FPU EQU 128
		51
		52	SRC2_FPU EQU 256
		53	SRC2_REAL EQU 512
		54	SRC2_DMEM EQU 1024
		55	SRC2_DIMM EQU 2048
		56	SRC2_CONST EQU 4096
		57
		58	STR_REG EQU 0
		59	STR_SCI EQU 32768
		60
		61	FPU_PI EQU 1
		62	FPU_NAPIER EQU 2
		63
		64	XAM_VALID EQU 1
		65	XAM_ZERO EQU 2
		66	XAM_NEG EQU 4
		67	XAM_SMALL EQU 8
		68	XAM_INFINIT EQU 16
		69
		70	CMP_EQU EQU 1
		71	CMP_GREATER EQU 2
		72	CMP_LOWER EQU 4
		73
		74
		75
		76
		77	; #########################################################################
		78	;
		79	; FpuFLtoA
		80	;
		81	;##########################################################################
		82
		83	; -----------------------------------------------------------------------
		84	; This procedure was written by Raymond Filiatreault, December 2002
		85	; and modified April 2003. A minor flaw was corrected in July 2003.
		86	; Modified March 2004 to avoid any potential data loss from the FPU
		87	;
		88	; This FpuFLtoA function converts an 80-bit REAL number (Src) to its
		89	; decimal representation as a zero terminated alphanumeric string which
		90	; is returned at the specified memory destination unless an invalid
		91	; operation is reported by the FPU or the definition of the parameters
		92	; (with uID) is invalid.
		93	;
		94	; The format of the string can be specified as regular (default) or
		95	; scientific notation. The number of decimal places returned must also be
		96	; specified but the total number of significant digits must not exceed 16.
		97	; When the regular format is specified, the integer portion can also be
		98	; padded with preceding spaces to position the decimal point at a
		99	; specified location from the start of the string.
		100	;
		101	; The source can be an 80-bit REAL number from the FPU itself or from
		102	; memory.
		103	;
		104	; The source is not checked for validity. This is the programmer's
		105	; responsibility.
		106	;
		107	; This procedure is based on using an FPU instruction to convert the
		108	; REAL number into a specific packed decimal format. After unpacking,
		109	; the decimal point is positioned as required.
		110	;
		111	; Only EAX is used to return error or success. All other CPU registers
		112	; are preserved. All FPU registers are preserved.
		113	;
		114	; -----------------------------------------------------------------------
		115
		116
		117	; #########################################################################
		118	align 4
		119	proc FpuFLtoA stdcall, lpSrc:DWORD, lpDecimal:DWORD, lpDest:DWORD, uID:DWORD
		120
		121	locals
		122	tempdw dd ?
		123	esize dd ?
		124	Padding dd ?
		125	Decimal dd ?
		126	content: times 108 db ?
		127	tempst dt ?
		128	bcdstr dt ?
		129	oldcw dw ?
		130	truncw dw ?
		131	unpacked: times 20 db ?
		132	endl
		133
		134	;get the specified number of decimals for result
		135	;and make corrections if necessary
		136
		137	mov eax,[lpDecimal]
		138	test [uID],SRC2_DMEM
		139	jz @F
		140	mov eax,[eax] ;get the decimals from memory
		141	@@:
		142	push eax
		143	movzx eax,al ;low byte - number of decimal digits
		144	cmp eax,15
		145	jbe @F
		146	mov eax,15 ;a maximum of 15 decimals is allowed
		147	@@:
		148	mov [Decimal],eax
		149	pop eax
		150	movzx eax,ah ;2nd byte - number of char before decimal point
		151	cmp eax,17
		152	jbe @F
		153	mov eax,17 ;a maximum of 17 characters is allowed
		154	@@:
		155	mov [Padding],eax
		156
		157	test [uID],SRC1_FPU ;is data taken from FPU?
		158	jz @F ;continue if not
		159
		160	;-------------------------------
		161	;check if top register is empty
		162	;-------------------------------
		163
		164	fxam ;examine its content
		165	fstsw ax ;store results in AX
		166	fwait ;for precaution
		167	sahf ;transfer result bits to CPU flag
		168	jnc @F ;not empty if Carry flag not set
		169	jpe @F ;not empty if Parity flag set
		170	jz srcerr1 ;empty if Zero flag set
		171
		172	@@:
		173	fsave [content]
		174
		175	;----------------------------------------
		176	;check source for Src and load it to FPU
		177	;----------------------------------------
		178
		179	test [uID],SRC1_FPU
		180	jz @F
		181	lea eax,[content]
		182	fld tbyte [eax+28]
		183	jmp dest0
		184
		185	@@:
		186	test [uID],SRC1_REAL ;is Src an 80-bit REAL in memory?
		187	jz srcerr ;no proper source identificaiton
		188	mov eax,[lpSrc]
		189	fld tbyte [eax]
		190	jmp dest0 ;go complete process
		191
		192	srcerr:
		193	frstor [content]
		194	srcerr1:
		195	push edi
		196	mov edi,[lpDest]
		197	mov eax,"ERRO";ORRE"
		198	stosd
		199	mov ax,"R"
		200	stosw
		201	pop edi
		202	xor eax,eax
		203	ret
		204
		205	dest0:
		206
		207	;-------------------------------------------
		208	;first examine the value on FPU for validity
		209	;-------------------------------------------
		210
		211	fxam ;examine value on FPU
		212	fstsw ax ;get result
		213	fwait
		214	sahf ;transfer to CPU flags
		215	jz maybezero
		216	jpo srcerr ;C3=0 and C2=0 would be NAN or unsupported
		217	jnc getnumsize ;continue if normal finite number
		218
		219	;--------------------------------
		220	;value to be converted = INFINITY
		221	;--------------------------------
		222
		223	push ecx
		224	push esi
		225	push edi
		226	mov edi,[lpDest]
		227	mov al,"+"
		228	test ah,2 ;C1 field = sign
		229	jz @F
		230	mov al,"-"
		231	@@:
		232	stosb
		233	mov eax,"INFI";IFNI"
		234	stosd
		235	mov eax,"NITY";YTIN"
		236	stosd
		237	jmp finish
		238
		239	;-------------------------
		240	;value to be converted = 0
		241	;-------------------------
		242
		243	maybezero:
		244	jpe getnumsize ;would be denormalized number
		245	fstp st0 ;flush that 0 value off the FPU
		246	push ecx
		247	push esi
		248	push edi
		249	mov edi,[lpDest]
		250	test [uID],STR_SCI ;scientific notation?
		251	jnz @F ;no padding
		252	mov ecx,[Padding]
		253	sub ecx,2
		254	jle @F ;no padding specified or necessary
		255	mov al," "
		256	rep stosb
		257	@@:
		258	mov ax,3020h ;" 0" szstring
		259	stosw ;write it
		260	jmp finish
		261
		262	;---------------------------
		263	; get the size of the number
		264	;---------------------------
		265
		266	getnumsize:
		267	fldlg2 ;log10(2)
		268	fld st1 ;copy Src
		269	fabs ;insures a positive value
		270	fyl2x ;->[log2(Src)]*[log10(2)] = log10(Src)
		271
		272	fstcw [oldcw] ;get current control word
		273	fwait
		274	mov ax,[oldcw]
		275	or ax,0c00h ;code it for truncating
		276	mov [truncw],ax
		277	fldcw [truncw] ;insure rounding code of FPU to truncating
		278
		279	fist [esize] ;store characteristic of logarithm
		280	fldcw [oldcw] ;load back the former control word
		281
		282	ftst ;test logarithm for its sign
		283	fstsw ax ;get result
		284	fwait
		285	sahf ;transfer to CPU flags
		286	sbb [esize],0 ;decrement esize if log is negative
		287	fstp st0 ;get rid of the logarithm
		288
		289	;-----------------------------------------------------------------------
		290	; get the power of 10 required to generate an integer with the specified
		291	; number of significant digits
		292	;-----------------------------------------------------------------------
		293
		294	mov eax,[uID]
		295	and eax,STR_SCI
		296	jnz .els0 ;regular decimal notation
		297	mov eax,[esize]
		298	or eax,eax ;check if number is < 1
		299	js @F
		300	; .if eax > 15 ;if number is >= 10^16
		301	cmp eax,15
		302	jbe .endif0
		303	or [uID],STR_SCI ;switch to scientific notation
		304	mov [Decimal],15 ;insures 15 decimal places in result
		305	jmp scific
		306	.endif0:
		307	add eax,[Decimal]
		308	; .if eax > 15 ;if integer + decimal digits > 16
		309	cmp eax,15
		310	jbe .endif1
		311	sub eax,15
		312	sub [Decimal],eax ;reduce decimal digits as required
		313	.endif1:
		314	@@:
		315	push [Decimal]
		316	pop [tempdw]
		317	jmp @f
		318	.els0: ;scientific notation
		319	scific:
		320	mov eax,[Decimal]
		321	sub eax,[esize]
		322	mov [tempdw],eax
		323	; .endif
		324	@@:
		325
		326	;----------------------------------------------------------------------------------------
		327	; multiply the number by the power of 10 to generate required integer and store it as BCD
		328	;----------------------------------------------------------------------------------------
		329
		330	;.if tempdw != 0
		331	cmp [tempdw],0
		332	je @f
		333	fild [tempdw]
		334	fldl2t
		335	fmulp st1,st0 ;->log2(10)*exponent
		336	fld st0
		337	frndint ;get the characteristic of the log
		338	fxch
		339	fsub st,st1 ;get only the fractional part but keep the characteristic
		340	f2xm1 ;->2^(fractional part)-1
		341	fld1
		342	faddp st1,st0 ;add 1 back
		343	fscale ;re-adjust the exponent part of the REAL number
		344	fstp st1 ;get rid of the characteristic of the log
		345	fmulp st1,st0 ;->16-digit integer
		346	;.endif
		347	@@:
		348
		349	fbstp [bcdstr] ;->TBYTE containing the packed digits
		350	fstsw ax ;retrieve exception flags from FPU
		351	fwait
		352	shr eax,1 ;test for invalid operation
		353	jc srcerr ;clean-up and return error
		354
		355	;------------------------------------------------------------------------------
		356	; unpack BCD, the 10 bytes returned by the FPU being in the little-endian style
		357	;------------------------------------------------------------------------------
		358
		359	push ecx
		360	push esi
		361	push edi
		362	lea esi,[bcdstr+9] ;go to the most significant byte (sign byte)
		363	lea edi,[unpacked]
		364	mov eax,3020h
		365	mov cl,byte [esi] ;sign byte
		366	; .if cl == 80h
		367	cmp cl,0x80
		368	jne @f
		369	mov al,"-" ;insert sign if negative number
		370	; .endif
		371	@@:
		372	stosw
		373	mov ecx,9
		374	@@:
		375	dec esi
		376	movzx eax,byte [esi]
		377	ror ax,4
		378	ror ah,4
		379	add ax,3030h
		380	stosw
		381	dec ecx
		382	jnz @B
		383
		384	mov edi,[lpDest]
		385	lea esi,[unpacked]
		386	test [uID],STR_SCI ;scientific notation?
		387	jnz scientific
		388
		389	;************************
		390	; REGULAR STRING NOTATION
		391	;************************
		392
		393	;------------------------------
		394	; check if padding is specified
		395	;------------------------------
		396
		397	mov ecx,[Padding]
		398	or ecx,ecx ;check if padding is specified
		399	jz nopadding
		400
		401	mov edx,2 ;at least 1 integer + sign
		402	mov eax,[esize]
		403	or eax,eax
		404	js @F ;only 1 integer digit if size is < 1
		405	add edx,eax ;->number of integer digits
		406	@@:
		407	sub ecx,edx
		408	jle nopadding
		409	mov al," "
		410	rep stosb
		411
		412	nopadding:
		413	pushfd ;save padding flags
		414	movsb ;insert sign
		415	mov ecx,1 ;at least 1 integer digit
		416	mov eax,[esize]
		417	or eax,eax ;is size negative (i.e. number smaller than 1)
		418	js @F
		419	add ecx,eax
		420	@@:
		421	mov eax,[Decimal]
		422	add eax,ecx ;->total number of digits to be displayed
		423	sub eax,19
		424	sub esi,eax ;address of 1st digit to be displayed
		425	pop eax ;retrieve padding flags in EAX
		426	; .if byte ptr[esi-1] == "1"
		427	cmp byte [esi-1],"1"
		428	jne @f
		429	dec esi
		430	inc ecx
		431	push eax ;transfer padding flags through stack
		432	popfd ;retrieve padding flags
		433	jle @F ;no padding was necessary
		434	dec edi ;adjust for one less padding byte
		435	; .endif
		436	@@:
		437	@@:
		438	rep movsb ;copy required integer digits
		439	mov ecx,[Decimal]
		440	or ecx,ecx
		441	jz @F
		442	mov al,"."
		443	stosb
		444	rep movsb ;copy required decimal digits
		445	@@:
		446	jmp finish
		447
		448	;********************
		449	; SCIENTIFIC NOTATION
		450	;********************
		451
		452	scientific:
		453	movsb ;insert sign
		454	mov ecx,[Decimal]
		455	mov eax,18
		456	sub eax,ecx
		457	add esi,eax
		458	cmp byte [esi-1],"1"
		459	pushfd ;save flags for extra "1"
		460	jnz @F
		461	dec esi
		462	@@:
		463	movsb ;copy the integer
		464	mov al,"."
		465	stosb
		466	rep movsb ;copy the decimal digits
		467
		468	mov al,"E"
		469	stosb
		470	mov al,"+"
		471	mov ecx,[esize]
		472	popfd ;retrieve flags for extra "1"
		473	jnz @F ;no extra "1"
		474	inc ecx ;adjust exponent
		475	@@:
		476	or ecx,ecx
		477	jns @F
		478	mov al,"-"
		479	neg ecx ;make number positive
		480	@@:
		481	stosb ;insert proper sign
		482
		483	;Note: the absolute value of the size could not exceed 4931
		484
		485	mov eax,ecx
		486	mov cl,100
		487	div cl ;->thousands & hundreds in AL, tens & units in AH
		488	push eax
		489	and eax,0ffh ;keep only the thousands & hundreds
		490	mov cl,10
		491	div cl ;->thousands in AL, hundreds in AH
		492	add ax,3030h ;convert to characters
		493	stosw ;insert them
		494	pop eax
		495	shr eax,8 ;get the tens & units in AL
		496	div cl ;tens in AL, units in AH
		497	add ax,3030h ;convert to characters
		498	stosw ;insert them
		499
		500	finish:
		501	xor eax,eax
		502	stosb ;string terminating 0
		503	pop edi
		504	pop esi
		505	pop ecx
		506
		507	frstor [content]
		508
		509	or al,1 ;to insure EAX!=0
		510	ret
		511
		512	endp
		513
		514	; #########################################################################
		515
		516
		517	align 4
		518
		519	; #########################################################################
		520	; FpuCos
		521	;##########################################################################
		522	;
		523	; cos(Src) -> Dest
		524	FpuCos:
		525	test [flags],(1 shl 30)
		526	jz @f ;jump if angle already in radians
		527	fldpi ;load pi (3.14159...) on FPU
		528	fmulp
		529	test [flags],(1 shl 31)
		530	jnz .1
		531	pushd 200
		532	jmp .2
		533	.1: pushd 180
		534	.2: fidiv dword [esp] ;value now in radians
		535	fwait
		536	add esp,4 ;clean the stack
		537	@@: fldpi
		538	fadd st,st ;->2pi
		539	fxch
		540
		541	@@: fprem ;reduce the angle
		542	fcos
		543	fstsw ax ;retrieve exception flags from FPU
		544	fwait
		545	shr al,1 ;test for invalid operation
		546	sahf ;transfer to the CPU flags
		547	jpe @B ;reduce angle again if necessary
		548	fstp st1 ;get rid of the 2pi
		549	ret
		550
		551	align 4
		552	; #########################################################################
		553	; FpuSin
		554	;##########################################################################
		555	;
		556	; sin(Src) -> Dest
		557	FpuSin:
		558	test [flags],(1 shl 30)
		559	jz @f ;jump if angle already in radians
		560	fldpi ;load pi (3.14159...) on FPU
		561	fmulp
		562	test [flags],(1 shl 31)
		563	jnz .1
		564	pushd 200
		565	jmp .2
		566	.1: pushd 180
		567	.2: fidiv dword [esp] ;value now in radians
		568	fwait
		569	add esp,4 ;clean the stack
		570	@@:
		571	fldpi
		572	fadd st,st ;->2pi
		573	fxch
		574
		575	fprem ;reduce the angle
		576	fsin
		577	fstp st1 ;get rid of the 2pi
		578	ret
		579
		580	align 4
		581	; #########################################################################
		582	; FpuArctan
		583	;##########################################################################
		584	;
		585	; atan(Src) -> Dest
		586	FpuArctan:
		587	fld1
		588	fpatan
		589	test [flags],(1 shl 30)
		590	jz @F ;jump if angle is required in radians
		591	test [flags],(1 shl 31)
		592	jnz .1
		593	pushd 200
		594	jmp .2
		595	.1: pushd 180
		596	.2: fimul dword [esp] ;*180 degrees
		597	fldpi ;load pi (3.14159...) on FPU
		598	fdivp ;*180/pi, angle now in degrees
		599	add esp,4 ;clean CPU stack
		600
		601	ftst ;check for negative angle
		602	fstsw ax ;retrieve status word from FPU
		603	fwait
		604	sahf
		605	jnc @F ;jump if positive number
		606	test [flags],(1 shl 31)
		607	jnz .3
		608	pushd 400
		609	jmp .4
		610	.3: pushd 360
		611	.4: fiadd dword [esp] ;angle now 0-360
		612	fwait
		613	add esp,4 ;clean CPU stack
		614
		615	@@:
		616	ret
		617
		618	align 4
		619	; #########################################################################
		620	; FpuTan
		621	;##########################################################################
		622
		623	; a = tan(x)
		624	FpuTan:
		625	fldpi ;load pi (3.14159...) on FPU
		626	fadd st,st ;->2pi
		627	fxch
		628	test [flags],(1 shl 30)
		629	jz @F ;jump if angle already in radians
		630	test [flags],(1 shl 31)
		631	jnz .1
		632	pushd 400
		633	jmp .2
		634	.1: pushd 360
		635	.2: fmul st,st1
		636	fidiv dword [esp] ;value now in radians
		637	pop eax ;clean the stack
		638	@@: fprem ;reduce the angle
		639	fptan
		640
		641	fstp st ;get rid of the 1
		642	fstp st1 ;get rid of the 2pi
		643	ret
		644
		645	align 4
		646	; #########################################################################
		647	; FpuArccos
		648	;##########################################################################
		649	; sqrt(1-Src^2)
		650	; acos(Src) = atan ------------- -> Dest
		651	; Src
		652
		653	FpuArccos:
		654	fld st ;copy cosine value
		655	fmul st0,st1 ;cos^2
		656	fld1
		657	fsubrp ;1-cos^2 = sin^2
		658	fsqrt ;->sin
		659	fxch
		660	fpatan ;i.e. arctan(sin/cos)
		661
		662	test [flags],(1 shl 30)
		663	jz @F ;jump if angle is required in radians
		664	test [flags],(1 shl 31)
		665	jnz .1
		666	pushd 200
		667	jmp .2
		668	.1: pushd 180
		669	.2: fimul dword [esp] ;*180 degrees
		670	fldpi ;load pi (3.14159...) on FPU
		671	fdivp ;*180/pi, angle now in degrees
		672	pop eax ;clean CPU stack
		673	@@:
		674	ret
		675
		676	align 4
		677	; #########################################################################
		678	; FpuArcsin
		679	;##########################################################################
		680	; Src
		681	; asin(Src) = atan ------------- -> Dest
		682	; sqrt(1-Src^2)
		683	FpuArcsin:
		684	fld st0 ;copy sine value
		685	fmul st0,st0 ;sin^2
		686	fld1
		687	fsubrp ;1-sin^2 = cos^2
		688	fsqrt ;->cos
		689	fpatan ;i.e. arctan(sin/cos) = arcsin
		690	test [flags],(1 shl 30)
		691	jz @F ;jump if angle is required in radians
		692	test [flags],(1 shl 31)
		693	jnz .1
		694	pushd 200
		695	jmp .2
		696	.1: pushd 180
		697	.2: fimul dword [esp] ;*180 degrees
		698	fldpi ;load pi (3.14159...) on FPU
		699	fdivrp ;*180/pi, angle now in degrees
		700	add esp,4 ;clean CPU stack
		701	@@:
		702	ret
		703
		704	align 4
		705	; #########################################################################
		706	; FpuEexpX
		707	;##########################################################################
		708
		709	; e^(Src) = antilog2[ log2(e) * Src ] -> Dest
		710
		711	FpuEexpX:
		712
		713	fldl2e ;->log2(e)
		714	fmulp ;->log2(e)*Src
		715
		716	fld st0 ;copy the logarithm
		717	frndint ;keep only the characteristic
		718	fsub st1,st ;keeps only the mantissa
		719	fxch ;get the mantissa on top
		720
		721	f2xm1 ;->2^(mantissa)-1
		722	fld1
		723	faddp ;add 1 back
		724
		725	fscale ;scale it with the characteristic
		726
		727	fstp st1 ;get rid of the characteristic
		728	ret
		729
		730	align 4
		731	; #########################################################################
		732	; FpuXexpY
		733	;##########################################################################
		734
		735	; Src1^Src2 = antilog2[ log2(Src1) * Src2 ] -> Dest
		736
		737	FpuXexpY:
		738	fxch ;set up FPU registers for next operation
		739	fyl2x ;->log2(Src1)*exponent
		740
		741	fld st0 ;copy the logarithm
		742	frndint ;keep only the characteristic
		743	fsub st1,st ;keeps only the mantissa
		744	fxch ;get the mantissa on top
		745
		746	f2xm1 ;->2^(mantissa)-1
		747	fld1
		748	faddp ;add 1 back
		749
		750	fscale ;scale it with the characteristic
		751
		752	fstp st1 ;overwrite the characteristic
		753	ret
		754
		755
		756	if 0
		757	exp:
		758	.N equ 10
		759	xor eax,eax
		760	mov ecx,.N
		761	fld1
		762	.0: dec ecx
		763	jz .end
		764	mov eax,.N
		765	sub eax,ecx
		766	mov [.d],eax
		767	fild [.d]
		768	@@: dec eax
		769	jz @f
		770	mov [.d],eax
		771	fild [.d]
		772	fmulp
		773	jmp @b
		774	@@: mov eax,.N
		775	sub eax,ecx
		776	fld st2
		777	@@: dec eax
		778	jz @f
		779	fld st3
		780	fmulp
		781	jmp @b
		782	@@: fdivrp
		783	faddp
		784	jmp .0
		785	.end: fxch
		786	fstp st0
		787	ret
		788	.d dd 0
		789	endf

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(root)/programs/emulator/PrMK/trunk/MASMFpuLib.asm @ 1937 – Rev 1863