diff options
Diffstat (limited to 'target-ppc')
| -rw-r--r-- | target-ppc/dfp_helper.c | 97 | ||||
| -rw-r--r-- | target-ppc/helper.h | 2 | ||||
| -rw-r--r-- | target-ppc/translate.c | 4 |
3 files changed, 103 insertions, 0 deletions
diff --git a/target-ppc/dfp_helper.c b/target-ppc/dfp_helper.c index e5574b5a30..23f85c4eec 100644 --- a/target-ppc/dfp_helper.c +++ b/target-ppc/dfp_helper.c @@ -376,6 +376,23 @@ static inline void dfp_makeQNaN(decNumber *dn) dn->bits |= DECNAN; } +static inline int dfp_get_digit(decNumber *dn, int n) +{ + assert(DECDPUN == 3); + int unit = n / DECDPUN; + int dig = n % DECDPUN; + switch (dig) { + case 0: + return dn->lsu[unit] % 10; + case 1: + return (dn->lsu[unit] / 10) % 10; + case 2: + return dn->lsu[unit] / 100; + default: + assert(0); + } +} + #define DFP_HELPER_TAB(op, dnop, postprocs, size) \ void helper_##op(CPUPPCState *env, uint64_t *t, uint64_t *a, uint64_t *b) \ { \ @@ -703,3 +720,83 @@ void helper_##op(CPUPPCState *env, uint64_t *t, uint64_t *a, \ DFP_HELPER_QUA(dqua, 64) DFP_HELPER_QUA(dquaq, 128) + +static void _dfp_reround(uint8_t rmc, int32_t ref_sig, int32_t xmax, + struct PPC_DFP *dfp) +{ + int msd_orig, msd_rslt; + + if (unlikely((ref_sig == 0) || (dfp->b.digits <= ref_sig))) { + dfp->t = dfp->b; + if (decNumberIsSNaN(&dfp->b)) { + dfp_makeQNaN(&dfp->t); + dfp_set_FPSCR_flag(dfp, FP_VX | FP_VXSNAN, FPSCR_VE); + } + return; + } + + /* Reround is equivalent to quantizing b with 1**E(n) where */ + /* n = exp(b) + numDigits(b) - reference_significance. */ + + decNumberFromUInt32(&dfp->a, 1); + dfp->a.exponent = dfp->b.exponent + dfp->b.digits - ref_sig; + + if (unlikely(dfp->a.exponent > xmax)) { + dfp->t.digits = 0; + dfp->t.bits &= ~DECNEG; + dfp_makeQNaN(&dfp->t); + dfp_set_FPSCR_flag(dfp, FP_VX | FP_VXCVI, FPSCR_VE); + return; + } + + dfp_quantize(rmc, dfp); + + msd_orig = dfp_get_digit(&dfp->b, dfp->b.digits-1); + msd_rslt = dfp_get_digit(&dfp->t, dfp->t.digits-1); + + /* If the quantization resulted in rounding up to the next magnitude, */ + /* then we need to shift the significand and adjust the exponent. */ + + if (unlikely((msd_orig == 9) && (msd_rslt == 1))) { + + decNumber negone; + + decNumberFromInt32(&negone, -1); + decNumberShift(&dfp->t, &dfp->t, &negone, &dfp->context); + dfp->t.exponent++; + + if (unlikely(dfp->t.exponent > xmax)) { + dfp_makeQNaN(&dfp->t); + dfp->t.digits = 0; + dfp_set_FPSCR_flag(dfp, FP_VX | FP_VXCVI, FP_VE); + /* Inhibit XX in this case */ + decContextClearStatus(&dfp->context, DEC_Inexact); + } + } +} + +#define DFP_HELPER_RRND(op, size) \ +void helper_##op(CPUPPCState *env, uint64_t *t, uint64_t *a, \ + uint64_t *b, uint32_t rmc) \ +{ \ + struct PPC_DFP dfp; \ + int32_t ref_sig = *a & 0x3F; \ + int32_t xmax = ((size) == 64) ? 369 : 6111; \ + \ + dfp_prepare_decimal##size(&dfp, 0, b, env); \ + \ + _dfp_reround(rmc, ref_sig, xmax, &dfp); \ + decimal##size##FromNumber((decimal##size *)dfp.t64, &dfp.t, \ + &dfp.context); \ + QUA_PPs(&dfp); \ + \ + if (size == 64) { \ + t[0] = dfp.t64[0]; \ + } else if (size == 128) { \ + t[0] = dfp.t64[HI_IDX]; \ + t[1] = dfp.t64[LO_IDX]; \ + } \ +} + +DFP_HELPER_RRND(drrnd, 64) +DFP_HELPER_RRND(drrndq, 128) diff --git a/target-ppc/helper.h b/target-ppc/helper.h index 362e9a80df..776d4d731f 100644 --- a/target-ppc/helper.h +++ b/target-ppc/helper.h @@ -640,3 +640,5 @@ DEF_HELPER_5(dquai, void, env, fprp, fprp, i32, i32) DEF_HELPER_5(dquaiq, void, env, fprp, fprp, i32, i32) DEF_HELPER_5(dqua, void, env, fprp, fprp, fprp, i32) DEF_HELPER_5(dquaq, void, env, fprp, fprp, fprp, i32) +DEF_HELPER_5(drrnd, void, env, fprp, fprp, fprp, i32) +DEF_HELPER_5(drrndq, void, env, fprp, fprp, fprp, i32) diff --git a/target-ppc/translate.c b/target-ppc/translate.c index 00dbfa8551..0647a4b063 100644 --- a/target-ppc/translate.c +++ b/target-ppc/translate.c @@ -8380,6 +8380,8 @@ GEN_DFP_T_B_U32_U32_Rc(dquai, SIMM5, RMC) GEN_DFP_T_B_U32_U32_Rc(dquaiq, SIMM5, RMC) GEN_DFP_T_A_B_I32_Rc(dqua, RMC) GEN_DFP_T_A_B_I32_Rc(dquaq, RMC) +GEN_DFP_T_A_B_I32_Rc(drrnd, RMC) +GEN_DFP_T_A_B_I32_Rc(drrndq, RMC) /*** SPE extension ***/ /* Register moves */ @@ -11331,6 +11333,8 @@ GEN_DFP_TE_T_B_RMC_Rc(dquai, 0x03, 0x02), GEN_DFP_TE_Tp_Bp_RMC_Rc(dquaiq, 0x03, 0x02), GEN_DFP_T_A_B_RMC_Rc(dqua, 0x03, 0x00), GEN_DFP_Tp_Ap_Bp_RMC_Rc(dquaq, 0x03, 0x00), +GEN_DFP_T_A_B_RMC_Rc(drrnd, 0x03, 0x01), +GEN_DFP_Tp_A_Bp_RMC_Rc(drrndq, 0x03, 0x01), #undef GEN_SPE #define GEN_SPE(name0, name1, opc2, opc3, inval0, inval1, type) \ GEN_OPCODE_DUAL(name0##_##name1, 0x04, opc2, opc3, inval0, inval1, type, PPC_NONE) |