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+|
+| sint.sa 3.1 12/10/90
+|
+| The entry point sINT computes the rounded integer
+| equivalent of the input argument, sINTRZ computes
+| the integer rounded to zero of the input argument.
+|
+| Entry points sint and sintrz are called from do_func
+| to emulate the fint and fintrz unimplemented instructions,
+| respectively. Entry point sintdo is used by bindec.
+|
+| Input: (Entry points sint and sintrz) Double-extended
+| number X in the ETEMP space in the floating-point
+| save stack.
+| (Entry point sintdo) Double-extended number X in
+| location pointed to by the address register a0.
+| (Entry point sintd) Double-extended denormalized
+| number X in the ETEMP space in the floating-point
+| save stack.
+|
+| Output: The function returns int(X) or intrz(X) in fp0.
+|
+| Modifies: fp0.
+|
+| Algorithm: (sint and sintrz)
+|
+| 1. If exp(X) >= 63, return X.
+| If exp(X) < 0, return +/- 0 or +/- 1, according to
+| the rounding mode.
+|
+| 2. (X is in range) set rsc = 63 - exp(X). Unnormalize the
+| result to the exponent $403e.
+|
+| 3. Round the result in the mode given in USER_FPCR. For
+| sintrz, force round-to-zero mode.
+|
+| 4. Normalize the rounded result; store in fp0.
+|
+| For the denormalized cases, force the correct result
+| for the given sign and rounding mode.
+|
+| Sign(X)
+| RMODE + -
+| ----- --------
+| RN +0 -0
+| RZ +0 -0
+| RM +0 -1
+| RP +1 -0
+|
+|
+| Copyright (C) Motorola, Inc. 1990
+| All Rights Reserved
+|
+| THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA
+| The copyright notice above does not evidence any
+| actual or intended publication of such source code.
+
+|SINT idnt 2,1 | Motorola 040 Floating Point Software Package
+
+ |section 8
+
+#include "fpsp.h"
+
+ |xref dnrm_lp
+ |xref nrm_set
+ |xref round
+ |xref t_inx2
+ |xref ld_pone
+ |xref ld_mone
+ |xref ld_pzero
+ |xref ld_mzero
+ |xref snzrinx
+
+|
+| FINT
+|
+ .global sint
+sint:
+ bfextu FPCR_MODE(%a6){#2:#2},%d1 |use user's mode for rounding
+| ;implicitly has extend precision
+| ;in upper word.
+ movel %d1,L_SCR1(%a6) |save mode bits
+ bras sintexc
+
+|
+| FINT with extended denorm inputs.
+|
+ .global sintd
+sintd:
+ btstb #5,FPCR_MODE(%a6)
+ beq snzrinx |if round nearest or round zero, +/- 0
+ btstb #4,FPCR_MODE(%a6)
+ beqs rnd_mns
+rnd_pls:
+ btstb #sign_bit,LOCAL_EX(%a0)
+ bnes sintmz
+ bsr ld_pone |if round plus inf and pos, answer is +1
+ bra t_inx2
+rnd_mns:
+ btstb #sign_bit,LOCAL_EX(%a0)
+ beqs sintpz
+ bsr ld_mone |if round mns inf and neg, answer is -1
+ bra t_inx2
+sintpz:
+ bsr ld_pzero
+ bra t_inx2
+sintmz:
+ bsr ld_mzero
+ bra t_inx2
+
+|
+| FINTRZ
+|
+ .global sintrz
+sintrz:
+ movel #1,L_SCR1(%a6) |use rz mode for rounding
+| ;implicitly has extend precision
+| ;in upper word.
+ bras sintexc
+|
+| SINTDO
+|
+| Input: a0 points to an IEEE extended format operand
+| Output: fp0 has the result
+|
+| Exceptions:
+|
+| If the subroutine results in an inexact operation, the inx2 and
+| ainx bits in the USER_FPSR are set.
+|
+|
+ .global sintdo
+sintdo:
+ bfextu FPCR_MODE(%a6){#2:#2},%d1 |use user's mode for rounding
+| ;implicitly has ext precision
+| ;in upper word.
+ movel %d1,L_SCR1(%a6) |save mode bits
+|
+| Real work of sint is in sintexc
+|
+sintexc:
+ bclrb #sign_bit,LOCAL_EX(%a0) |convert to internal extended
+| ;format
+ sne LOCAL_SGN(%a0)
+ cmpw #0x403e,LOCAL_EX(%a0) |check if (unbiased) exp > 63
+ bgts out_rnge |branch if exp < 63
+ cmpw #0x3ffd,LOCAL_EX(%a0) |check if (unbiased) exp < 0
+ bgt in_rnge |if 63 >= exp > 0, do calc
+|
+| Input is less than zero. Restore sign, and check for directed
+| rounding modes. L_SCR1 contains the rmode in the lower byte.
+|
+un_rnge:
+ btstb #1,L_SCR1+3(%a6) |check for rn and rz
+ beqs un_rnrz
+ tstb LOCAL_SGN(%a0) |check for sign
+ bnes un_rmrp_neg
+|
+| Sign is +. If rp, load +1.0, if rm, load +0.0
+|
+ cmpib #3,L_SCR1+3(%a6) |check for rp
+ beqs un_ldpone |if rp, load +1.0
+ bsr ld_pzero |if rm, load +0.0
+ bra t_inx2
+un_ldpone:
+ bsr ld_pone
+ bra t_inx2
+|
+| Sign is -. If rm, load -1.0, if rp, load -0.0
+|
+un_rmrp_neg:
+ cmpib #2,L_SCR1+3(%a6) |check for rm
+ beqs un_ldmone |if rm, load -1.0
+ bsr ld_mzero |if rp, load -0.0
+ bra t_inx2
+un_ldmone:
+ bsr ld_mone
+ bra t_inx2
+|
+| Rmode is rn or rz; return signed zero
+|
+un_rnrz:
+ tstb LOCAL_SGN(%a0) |check for sign
+ bnes un_rnrz_neg
+ bsr ld_pzero
+ bra t_inx2
+un_rnrz_neg:
+ bsr ld_mzero
+ bra t_inx2
+
+|
+| Input is greater than 2^63. All bits are significant. Return
+| the input.
+|
+out_rnge:
+ bfclr LOCAL_SGN(%a0){#0:#8} |change back to IEEE ext format
+ beqs intps
+ bsetb #sign_bit,LOCAL_EX(%a0)
+intps:
+ fmovel %fpcr,-(%sp)
+ fmovel #0,%fpcr
+ fmovex LOCAL_EX(%a0),%fp0 |if exp > 63
+| ;then return X to the user
+| ;there are no fraction bits
+ fmovel (%sp)+,%fpcr
+ rts
+
+in_rnge:
+| ;shift off fraction bits
+ clrl %d0 |clear d0 - initial g,r,s for
+| ;dnrm_lp
+ movel #0x403e,%d1 |set threshold for dnrm_lp
+| ;assumes a0 points to operand
+ bsr dnrm_lp
+| ;returns unnormalized number
+| ;pointed by a0
+| ;output d0 supplies g,r,s
+| ;used by round
+ movel L_SCR1(%a6),%d1 |use selected rounding mode
+|
+|
+ bsr round |round the unnorm based on users
+| ;input a0 ptr to ext X
+| ; d0 g,r,s bits
+| ; d1 PREC/MODE info
+| ;output a0 ptr to rounded result
+| ;inexact flag set in USER_FPSR
+| ;if initial grs set
+|
+| normalize the rounded result and store value in fp0
+|
+ bsr nrm_set |normalize the unnorm
+| ;Input: a0 points to operand to
+| ;be normalized
+| ;Output: a0 points to normalized
+| ;result
+ bfclr LOCAL_SGN(%a0){#0:#8}
+ beqs nrmrndp
+ bsetb #sign_bit,LOCAL_EX(%a0) |return to IEEE extended format
+nrmrndp:
+ fmovel %fpcr,-(%sp)
+ fmovel #0,%fpcr
+ fmovex LOCAL_EX(%a0),%fp0 |move result to fp0
+ fmovel (%sp)+,%fpcr
+ rts
+
+ |end