dexp.u

操作系统SunOS 4.1.3版本的源码

	;			dnop tioe timsw halt;		titoreg;	rcsmsw ptr5;	

z.inrange:
|* First, check to see whether K<-1021.  If not, then UNDERFLOW.
|* Load K in RA, -1021 in RB and Integer compare:
	;			;				;		ptr5;		ptr5!c_sim1021
	;			i2cmp enrb halt;		regtoti;	rcssp ptr5;
	;			dnop;				;		ptr5;		ptr5!0x700+0xDD
	;			i2cmp enra halt;		regtoti;	rcssp ptr5;
	;			;				;		ptr5;		ptr5!0x700+0xDC
	jlt bail.under;		dnop enra enrb loaddp halt;	regtoti;	rcsmsw ptr5;
|* compute t = z*z and store in C register:
	;			dmul enra enrb loaddp halt;	regtoti;	rcslsw ptr5;
	;			dmul;				;		;
	;			dnop srccmul clkcc;		;		ptr5;	ptr5!c_dp5
	;			dnop enrb loaddp halt;		regtoti;	rcsmsw ptr5;
	;			dmul mulacreg enrb loaddp halt;	regtoti;	rcslsw ptr5;
	;			dmul mulacreg;			;		ptr5;	ptr5!c_dp4
	;			dnop enrb loaddp halt;		regtoti;	rcsmsw ptr5;
	;			dadd aluamul enrb loaddp halt;	regtoti;	rcslsw ptr5;
	;			dmul mulaalu mulbcreg;		;		;
	;			dmul mulaalu mulbcreg;		;		ptr5;	ptr5!c_dp3
	;			dnop enrb loaddp halt;		regtoti;	rcsmsw ptr5;
	;			dadd aluamul enrb loaddp halt;	regtoti;	rcslsw ptr5;
	;			dmul mulaalu mulbcreg;		;		;
	;			dmul mulaalu mulbcreg;		;		ptr5;	ptr5!c_dp2
	;			dnop enrb loaddp halt;		regtoti;	rcsmsw ptr5;
	;			dadd aluamul enrb loaddp halt;	regtoti;	rcslsw ptr5;
	;			dmul mulaalu mulbcreg;		;		;
	;			dmul mulaalu mulbcreg;		;		ptr5;	ptr5!c_dp1
	;			dnop enrb loaddp halt;		regtoti;	rcsmsw ptr5;
	;			dadd aluamul enrb loaddp halt;	regtoti;	rcslsw ptr5;
	;			dmul mulaalu mulbcreg;		;		;
	;			dmul mulaalu mulbcreg;		;		ptr5;	ptr5!0x700+0xDC
	;			dnop enrb loaddp halt;		regtoti;	rcsmsw ptr5;
	;			drsub aluamul enrb loaddp halt;	regtoti;	rcslsw ptr5;
	;			dnop;				;		ptr5;	ptr5!0x700+0xDE
	;			dnop srccalu clkcc tioe timsw halt;titoreg;	rcsmsw ptr5;
	;			dnop tioe tilsw halt;		titoreg;	rcslsw ptr5;
| Check to see if k = 0
	;			dnop;				;		ptr5;	ptr5!c_sizero
	;			i2cmp enrb halt;		regtoti;	rcssp ptr5;
	;			;				;		ptr5;	ptr5!0x700+0xDD
	;			i2cmp enra halt;		regtoti;	rcssp ptr5;
	;			;				;		ptr5;	ptr5!dtwo
	jne result.zero;	dnop enra loaddp halt;		regtoti;	rcsmsw ptr5;
| If zero, compute one - ((z*c)/(c-2.0)-z);   c in C register as well as in DE
	;			drsub alubcreg enra loaddp halt;regtoti;	rcslsw ptr5;
	;			dnop;				;		;
	;			dnop tioe timsw halt;		titotmp;	rcsmsw;
	;			dnop tioe tilsw halt;		titotmp;	rcslsw;
	;			dnop;				;		ptr5;	ptr5!0x700+0xDC
	;			dnop enrb loaddp halt;		regtoti;	rcsmsw ptr5;
	;			dmul mulacreg enrb loaddp halt;	regtoti;	rcslsw ptr5;
	;			dmul mulacreg;			;		;
	;			dnop;				;		;
	;			dnop enra tioe timsw loaddp halt;;		;
	;			dnop enra tioe tilsw loaddp halt;;		;
	;			ddiv enrb loaddp halt;		tmptoti;	rcsmsw;
	;			ddiv enrb loaddp halt;		tmptoti;	rcslsw;		
	;			dnop;				;		;
	;			dnop halt;			;		;
	;			dnop;				;		;
	;			dnop;				;		;
	;			dnop;				;		;
	;			dmul;				;		;
	;			dmul halt;			;		;
	;			dmul tioe timsw halt;		titotmp;	rcsmsw;
	;			dmul tioe tilsw halt;		titotmp;	rcslsw;
	;			dnop halt;			;		ptr5;	ptr5!0x700+0xDC
	;			dnop enrb loaddp halt;		regtoti;	rcsmsw ptr5;
	;			dnop enrb loaddp halt;		regtoti;	rcslsw ptr5;
	;			dnop;				;		;
	;			dnop enra loaddp halt;		tmptoti;	rcsmsw;
	;			dsub enra loaddp halt;		tmptoti;	rcslsw;
	;			dsub;				;		ptr5;	ptr5!done
	;			dnop enra loaddp halt;		regtoti;	rcsmsw ptr5;
	;			dsub alubalu enra loaddp halt;	regtoti;	rcslsw ptr5;
	;			dnop;				;		ptr1;
	;			dnop tioe tilsw halt;		titoreg;	rcslsw ptr1;
	call idle1;		dnop tioe timsw halt;		titoreg;	rcsmsw ptr1;

result.zero:
|* compute y = one -((lo-(z*c)/(2.0-c))-hi).  z in RB, c in C.  Ptr 5 with dtwo.
	;			dsub alubcreg;			;		;
	;			dnop;				;		;
	;			dnop tioe timsw halt;		titotmp;	rcsmsw;
	;			dnop tioe tilsw halt;		titotmp;	rcslsw;
	;			dnop;				;		ptr5;	ptr5!0x700+0xDC
	;			dnop enrb loaddp halt;		regtoti;	rcsmsw ptr5;
	;			dmul mulacreg enrb loaddp halt;	regtoti;	rcslsw ptr5;
	;			dmul mulacreg;			;		;
	;			dnop;				;		;
	;			dnop enra tioe timsw loaddp halt;;		;
	;			dnop enra tioe tilsw loaddp halt;;		;
	;			ddiv enrb loaddp halt;		tmptoti;	rcsmsw;
	;			ddiv enrb loaddp halt;		tmptoti;	rcslsw;		
	;			dnop;				;		;
	;			dnop halt;			;		;
	;			dnop;				;		;
	;			dnop;				;		;
	;			dnop;				;		;
	;			dmul;				;		;
	;			dmul halt;			;		;
	;			dmul tioe timsw halt;		titotmp;	rcsmsw;
	;			dmul tioe tilsw halt;		titotmp;	rcslsw;
	;			dnop halt;			;		ptr5;	ptr5!0x700+0xDB
	;			dnop enra loaddp halt;		regtoti;	rcsmsw ptr5;
	;			dnop enra loaddp halt;		regtoti;	rcslsw ptr5;
	;			dnop;				;		;
	;			dnop enrb loaddp halt;		tmptoti;	rcsmsw;
	;			dsub enrb loaddp halt;		tmptoti;	rcslsw;
	;			dnop;				;		ptr5;	ptr5!0x700+0xDA
	;			dnop enra srccalu clkcc loaddp halt;regtoti;	rcsmsw ptr5;
	;			drsub alubcreg enra loaddp halt;regtoti;	rcslsw ptr5;
	;			drsub alubcreg;			;		ptr5;	ptr5!done
	;			dnop enra loaddp halt;		regtoti;	rcsmsw ptr5;
	;			dsub alubalu enra loaddp halt;	regtoti;	rcslsw ptr5;
	;			dnop;				;		ptr1;
	;			dnop tioe tilsw halt;		titoreg;	rcslsw ptr1;
	call scalbn;		dnop tioe timsw halt;		titoreg;	rcsmsw ptr1;
|* Do scalbn(y,k)  Add k to the exponent of y.  Y is in ptr2 register.  K is in SCRATCH_13
	pipe idl1;		snop halt;			;		imm2;
scalbn:
|* Y (DP) in ptr2
|* K (integer) in SCRATCH_13, 0x700+0xDD
	;			;				;		ptr5;		ptr5!0x700+0xDD
	;			i2cmp enra halt;		regtoti;	rcssp ptr5;
	;			;				;		ptr5;		ptr5!c_sitwo20 
      	;			imul enrb halt;			regtoti;	rcssp ptr5;
	;			;				;		;
	;			i2cmp enra tioe tisp halt;	;		;
	;			i2add enrb halt;		regtoti;	rcsmsw ptr1;
	;			;				;		ptr1;
	rtn;			tioe tisp halt;			titoreg;	rcsmsw ptr1;

dnotfinx:
|* In order to check for infinity or NAN, we need to look at msw[abs(x)] ANDed with 0x7FF00000,
|* which is the msw(infinity) and then compare with msw(infinity).  If it's equal, then we have
|* NAN or infinity.
|* Get msw[abs(x)] and store it in RA.  This is done by routing the output to the input.
	;			dabs tioe timsw;		;		;
	;			i2cmp enra srccalu clkcc tioe timsw halt;;	;
	;			;				;		ptr5;	ptr5!dinf
	;			i2land enrb loadsp halt;	regtoti;	ptr5;
	;			tioe tisp;			;		;
|* Unload MASKED msw[abs(x)] and store in RA, compare with lsw(infinity), already in RB.
	;			i2cmp enra tioe tisp loadsp halt;;		;
	;			;				;		ptr5;	ptr5!c_dln2_2
	jeq absx.in;		dnop enrb loaddp halt;		regtoti;	rcsmsw ptr5;
	;			dcmp aluacreg enrb loaddp halt;	regtoti;	rcslsw ptr5;
	rtn;			dnop;				;		ptr5;	ptr5!c_dln2_onehalf
|* If equal, then x is (NAN or Infinity), else, continue w/ algorithm.
|* If there was an error, it is due to underflow or overflow.  We will
|* deal with this later.  (i.e.  ignore error here).
|* 
absx.in: 
|* Result was a NAN or infinity.  
|* Need to check whether it was  (-infinity) as exp(-infinity)=0. 
|* Compare with x with (+inf).  If error, then x=NAN.  If eq, x=+inf.
|* If (-inf), then store 0 in reg2 and call idle.  Else, call idle. (reg 2 already
|* contains the result: exp(NAN) is NAN, exp(+inf)=+inf, exp(-inf)=0.
	;			;				;		ptr5;		ptr5!dinf
	;			dnop enra loaddp halt;		regtoti;	rcsmsw ptr5;
	;			dnop enra loaddp halt;		regtoti;	rcslsw ptr5;
	;			dnop enrb loaddp halt;		regtoti;	rcsmsw ptr2;
	;			dcmp enrb loaddp halt;		regtoti;	rcslsw ptr2;
	;			dcmp;				;		;	
|* If tierr, result was NAN. Bailout.
	jtierr bail.out cstat;	dcmp;				;		;
|* If result is not equal, x =  (-inf) so load ptr2 with 0.0; Else, return x.
	;			dcmp;				;		ptr5;		ptr5!dzero
	jeq retexp1;		dnop halt;			regtotmp;	rcsmsw ptr5;
	;			;				regtotmp;	rcslsw ptr5;
	;			;				;		ptr1;
	;			;				tmptoreg;	rcsmsw ptr1;
	call idle1;		;				tmptoreg;	rcslsw ptr1;
retexp1:
	;			;				regtotmp;	rcsmsw ptr2;
	;			;				regtotmp; 	rcslsw ptr2;
	;			;				;		ptr1;
	;			;				tmptoreg;	rcsmsw ptr1;
	call idle1;		;				tmptoreg;	rcslsw ptr1;

bail.out:
|* Signal an error to the cpu so it can recompute:  Replace ptr1 into ptr2.
        hng;                    halt;                           ;      		;
        call idle1;             halt;                           ;		;