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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 | | For details on the license for this file, please see the | file, README, in this same directory. |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