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Diffstat (limited to 'arch/m68k/fpsp040/sint.S')
| -rw-r--r-- | arch/m68k/fpsp040/sint.S | 246 |
1 files changed, 246 insertions, 0 deletions
diff --git a/arch/m68k/fpsp040/sint.S b/arch/m68k/fpsp040/sint.S new file mode 100644 index 000000000..0e92d4e5d --- /dev/null +++ b/arch/m68k/fpsp040/sint.S @@ -0,0 +1,246 @@ +| +| 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 |