Extend the machine/ieeefp.h that was inherited from i386 to support
the SSE mxcsr register as well. Since gcc will intermix SSE2 and x87 FP code, the fpsetround() etc mode had better be the same. There are hooks to enable these inlines to be instantiated inside libc for non-gcc or C++ callers. (g++ doesn't like the inlines that tried to extract an integer and convert it to an enum).
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peter
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e8952b93e7
commit
78fb90778a
@ -90,6 +90,15 @@ typedef enum {
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#define FP_RND_FLD 0xc00 /* round control field */
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#define FP_STKY_FLD 0x3f /* sticky flags field */
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/*
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* SSE mxcsr register bit field masks
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*/
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#define SSE_STKY_FLD 0x3f /* exception flags */
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#define SSE_DAZ_FLD 0x40 /* Denormals are zero */
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#define SSE_MSKS_FLD 0x1f80 /* exception masks field */
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#define SSE_RND_FLD 0x6000 /* rounding control */
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#define SSE_FZ_FLD 0x8000 /* flush to zero on underflow */
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/*
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* FP register bit field offsets
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*/
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@ -98,84 +107,185 @@ typedef enum {
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#define FP_RND_OFF 10 /* round control offset */
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#define FP_STKY_OFF 0 /* sticky flags offset */
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#ifdef __GNUC__
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/*
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* SSE mxcsr register bit field offsets
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*/
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#define SSE_STKY_OFF 0 /* exception flags offset */
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#define SSE_DAZ_OFF 6 /* DAZ exception mask offset */
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#define SSE_MSKS_OFF 7 /* other exception masks offset */
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#define SSE_RND_OFF 13 /* rounding control offset */
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#define SSE_FZ_OFF 15 /* flush to zero offset */
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#if defined(__GNUC__) && !defined(__cplusplus)
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#define __fldenv(addr) __asm __volatile("fldenv %0" : : "m" (*(addr)))
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#define __fnstenv(addr) __asm __volatile("fnstenv %0" : "=m" (*(addr)))
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#define __fldcw(addr) __asm __volatile("fldcw %0" : "=m" (*(addr)))
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#define __fnstcw(addr) __asm __volatile("fnstcw %0" : "=m" (*(addr)))
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#define __fnstsw(addr) __asm __volatile("fnstsw %0" : "=m" (*(addr)))
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#define __ldmxcsr(addr) __asm __volatile("ldmxcsr %0" : "=m" (*(addr)))
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#define __stmxcsr(addr) __asm __volatile("stmxcsr %0" : "=m" (*(addr)))
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/*
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* return the contents of a FP register
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* General notes about conflicting SSE vs FP status bits.
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* This code assumes that software will not fiddle with the control
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* bits of the SSE and x87 in such a way to get them out of sync and
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* still expect this to work. Break this at your peril.
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* Because I based this on the i386 port, the x87 state is used for
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* the fpget*() functions, and is shadowed into the SSE state for
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* the fpset*() functions. For dual source fpget*() functions, I
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* merge the two together. I think.
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*/
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static __inline__ int
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__fpgetreg(int _reg)
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{
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unsigned short _mem;
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/*-
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* This is more efficient than it looks. The switch gets optimized
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* away if _reg is constant.
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*
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* The default case only supports _reg == 0. We could handle more
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* registers (e.g., tags) using fnstenv, but the interface doesn't
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* support more.
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*/
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switch(_reg) {
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default:
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__fnstcw(&_mem);
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break;
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case FP_STKY_REG:
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__fnstsw(&_mem);
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break;
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}
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return _mem;
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/* Set rounding control */
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static __inline__ fp_rnd_t
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__fpgetround(void)
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{
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unsigned short _cw;
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__fnstcw(&_cw);
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return ((_cw & FP_RND_FLD) >> FP_RND_OFF);
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}
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static __inline__ fp_rnd_t
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__fpsetround(fp_rnd_t _m)
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{
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unsigned short _cw;
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unsigned int _mxcsr;
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fp_rnd_t _p;
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__fnstcw(&_cw);
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_p = (_cw & FP_RND_FLD) >> FP_RND_OFF;
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_cw &= ~FP_RND_FLD;
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_cw |= (_m << FP_RND_OFF) & FP_RND_FLD;
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__fldcw(&_cw);
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__stmxcsr(&_mxcsr);
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_mxcsr &= ~SSE_RND_FLD;
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_mxcsr |= (_m << SSE_RND_OFF) & SSE_RND_FLD;
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__ldmxcsr(&_mxcsr);
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return (_p);
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}
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/*
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* set a FP mode; return previous mode
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* Set precision for fadd/fsub/fsqrt etc x87 instructions
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* There is no equivalent SSE mode or control.
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*/
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static __inline__ int
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__fpsetreg(int _m, int _reg, int _fld, int _off)
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static __inline__ fp_prec_t
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__fpgetprec(void)
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{
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unsigned short _cw;
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__fnstcw(&_cw);
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return ((_cw & FP_PRC_FLD) >> FP_PRC_OFF);
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}
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static __inline__ fp_prec_t
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__fpsetprec(fp_rnd_t _m)
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{
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unsigned short _cw;
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fp_prec_t _p;
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__fnstcw(&_cw);
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_p = (_cw & FP_PRC_FLD) >> FP_PRC_OFF;
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_cw &= ~FP_PRC_FLD;
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_cw |= (_m << FP_PRC_OFF) & FP_PRC_FLD;
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__fldcw(&_cw);
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return (_p);
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}
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/*
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* Look at the exception masks
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* Note that x87 masks are inverse of the fp*() functions
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* API. ie: mask = 1 means disable for x87 and SSE, but
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* for the fp*() api, mask = 1 means enabled.
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*/
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static __inline__ fp_except_t
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__fpgetmask(void)
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{
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unsigned short _cw;
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__fnstcw(&_cw);
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return ((~_cw) & FP_MSKS_FLD);
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}
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static __inline__ fp_except_t
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__fpsetmask(fp_except_t _m)
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{
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unsigned short _cw;
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unsigned int _mxcsr;
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fp_except_t _p;
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__fnstcw(&_cw);
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_p = (~_cw) & FP_MSKS_FLD;
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_cw &= ~FP_MSKS_FLD;
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_cw |= (~_m) & FP_MSKS_FLD;
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__fldcw(&_cw);
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__stmxcsr(&_mxcsr);
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/* XXX should we clear non-ieee SSE_DAZ_FLD and SSE_FZ_FLD ? */
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_mxcsr &= ~SSE_MSKS_FLD;
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_mxcsr |= ((~_m) << SSE_MSKS_OFF) & SSE_MSKS_FLD;
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__ldmxcsr(&_mxcsr);
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return (_p);
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}
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/* See which sticky exceptions are pending, and reset them */
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static __inline__ fp_except_t
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__fpgetsticky(void)
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{
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unsigned short _sw;
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unsigned int _mxcsr;
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fp_except_t _ex;
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__fnstsw(&_sw);
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_ex = _sw & FP_STKY_FLD;
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__stmxcsr(&_mxcsr);
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_ex |= _mxcsr & SSE_STKY_FLD;
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return (_ex);
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}
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/* Note that this should really be called fpresetsticky() */
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static __inline__ fp_except_t
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__fpsetsticky(fp_except_t _m)
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{
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unsigned _env[7];
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unsigned _p;
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unsigned int _mxcsr;
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fp_except_t _p;
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/*
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* _reg == 0 could be handled better using fnstcw/fldcw.
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*/
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__fnstenv(_env);
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_p = (_env[_reg] & _fld) >> _off;
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_env[_reg] = (_env[_reg] & ~_fld) | (_m << _off & _fld);
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_p = _env[FP_STKY_REG] & _m;
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__stmxcsr(&_mxcsr);
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_p |= _mxcsr & SSE_STKY_FLD;
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_env[FP_STKY_REG] &= ~_m;
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__fldenv(_env);
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return _p;
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_mxcsr &= ~_m;
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__ldmxcsr(&_mxcsr);
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return (_p);
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}
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#endif /* __GNUC__ */
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#endif /* __GNUC__ && !__cplusplus */
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/*
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* SysV/386 FP control interface
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*/
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#define fpgetround() ((fp_rnd_t) \
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((__fpgetreg(FP_RND_REG) & FP_RND_FLD) >> FP_RND_OFF))
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#define fpsetround(m) ((fp_rnd_t) \
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__fpsetreg((m), FP_RND_REG, FP_RND_FLD, FP_RND_OFF))
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#define fpgetprec() ((fp_prec_t) \
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((__fpgetreg(FP_PRC_REG) & FP_PRC_FLD) >> FP_PRC_OFF))
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#define fpsetprec(m) ((fp_prec_t) \
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__fpsetreg((m), FP_PRC_REG, FP_PRC_FLD, FP_PRC_OFF))
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#define fpgetmask() ((fp_except_t) \
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((~__fpgetreg(FP_MSKS_REG) & FP_MSKS_FLD) >> FP_MSKS_OFF))
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#define fpsetmask(m) ((fp_except_t) \
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(~__fpsetreg(~(m), FP_MSKS_REG, FP_MSKS_FLD, FP_MSKS_OFF)) & \
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(FP_MSKS_FLD >> FP_MSKS_OFF))
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#define fpgetsticky() ((fp_except_t) \
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((__fpgetreg(FP_STKY_REG) & FP_STKY_FLD) >> FP_STKY_OFF))
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#define fpresetsticky(m) ((fp_except_t) \
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__fpsetreg(0, FP_STKY_REG, (m), FP_STKY_OFF))
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#define fpsetsticky(m) fpresetsticky(m)
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#if !defined(__IEEEFP_NOINLINES__) && !defined(__cplusplus) && defined(__GNUC__)
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#define fpsetround() __fpsetround()
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#define fpgetround(_m) __fpgetround(_m)
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#define fpgetprec() __fpgetprec()
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#define fpsetprec(_m) __fpsetprec(_m)
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#define fpgetmask() __fpgetmask()
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#define fpsetmask(_m) __fpsetmask(_m)
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#define fpgetsticky() __fpgetsticky()
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#define fpsetsticky(_m) __fpsetsticky(_m)
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/* Suppress prototypes in the MI header. */
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#define _IEEEFP_INLINED_ 1
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#else /* !__IEEEFP_NOINLINES__ && !__cplusplus && __GNUC__ */
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/* Augment the userland declarations */
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__BEGIN_DECLS
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extern fp_prec_t fpgetprec(void);
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extern fp_prec_t fpsetprec(fp_prec_t);
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__END_DECLS
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#endif /* !__IEEEFP_NOINLINES__ && !__cplusplus && __GNUC__ */
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#endif /* !_MACHINE_IEEEFP_H_ */
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