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| author | Tom Musta <tommusta@gmail.com> | 2014-04-21 15:55:21 -0500 |
|---|---|---|
| committer | Alexander Graf <agraf@suse.de> | 2014-06-16 13:24:32 +0200 |
| commit | 804e654a56549c2960f9c3857bec4f4d934b437e (patch) | |
| tree | d6b9734d7f2ce044d2a6a32fee1f4a3a13d0ae06 /target-ppc/dfp_helper.c | |
| parent | 297666eba0f6d73b5969763aec2b3f8ac4123b9a (diff) | |
| download | hqemu-804e654a56549c2960f9c3857bec4f4d934b437e.zip hqemu-804e654a56549c2960f9c3857bec4f4d934b437e.tar.gz | |
target-ppc: Introduce DFP Shift Significand
Add emulation of the PowerPC Decimal Floating Point Shift Significand
Left Immediate (dscli[q][.]) and DFP Shift Significant Right Immediate
(dscri[q][.]) instructions.
Signed-off-by: Tom Musta <tommusta@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Diffstat (limited to 'target-ppc/dfp_helper.c')
| -rw-r--r-- | target-ppc/dfp_helper.c | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/target-ppc/dfp_helper.c b/target-ppc/dfp_helper.c index adb9763..773803a 100644 --- a/target-ppc/dfp_helper.c +++ b/target-ppc/dfp_helper.c @@ -1220,3 +1220,98 @@ void helper_##op(CPUPPCState *env, uint64_t *t, uint64_t *a, uint64_t *b) \ DFP_HELPER_IEX(diex, 64) DFP_HELPER_IEX(diexq, 128) + +static void dfp_clear_lmd_from_g5msb(uint64_t *t) +{ + + /* The most significant 5 bits of the PowerPC DFP format combine bits */ + /* from the left-most decimal digit (LMD) and the biased exponent. */ + /* This routine clears the LMD bits while preserving the exponent */ + /* bits. See "Figure 80: Encoding of bits 0:4 of the G field for */ + /* Finite Numbers" in the Power ISA for additional details. */ + + uint64_t g5msb = (*t >> 58) & 0x1F; + + if ((g5msb >> 3) < 3) { /* LMD in [0-7] ? */ + *t &= ~(7ULL << 58); + } else { + switch (g5msb & 7) { + case 0: + case 1: + g5msb = 0; + break; + case 2: + case 3: + g5msb = 0x8; + break; + case 4: + case 5: + g5msb = 0x10; + break; + case 6: + g5msb = 0x1E; + break; + case 7: + g5msb = 0x1F; + break; + } + + *t &= ~(0x1fULL << 58); + *t |= (g5msb << 58); + } +} + +#define DFP_HELPER_SHIFT(op, size, shift_left) \ +void helper_##op(CPUPPCState *env, uint64_t *t, uint64_t *a, \ + uint32_t sh) \ +{ \ + struct PPC_DFP dfp; \ + unsigned max_digits = ((size) == 64) ? 16 : 34; \ + \ + dfp_prepare_decimal##size(&dfp, a, 0, env); \ + \ + if (sh <= max_digits) { \ + \ + decNumber shd; \ + unsigned special = dfp.a.bits & DECSPECIAL; \ + \ + if (shift_left) { \ + decNumberFromUInt32(&shd, sh); \ + } else { \ + decNumberFromInt32(&shd, -((int32_t)sh)); \ + } \ + \ + dfp.a.bits &= ~DECSPECIAL; \ + decNumberShift(&dfp.t, &dfp.a, &shd, &dfp.context); \ + \ + dfp.t.bits |= special; \ + if (special && (dfp.t.digits >= max_digits)) { \ + dfp.t.digits = max_digits - 1; \ + } \ + \ + decimal##size##FromNumber((decimal##size *)dfp.t64, &dfp.t, \ + &dfp.context); \ + } else { \ + if ((size) == 64) { \ + dfp.t64[0] = dfp.a64[0] & 0xFFFC000000000000ULL; \ + dfp_clear_lmd_from_g5msb(dfp.t64); \ + } else { \ + dfp.t64[HI_IDX] = dfp.a64[HI_IDX] & \ + 0xFFFFC00000000000ULL; \ + dfp_clear_lmd_from_g5msb(dfp.t64 + HI_IDX); \ + dfp.t64[LO_IDX] = 0; \ + } \ + } \ + \ + if ((size) == 64) { \ + t[0] = dfp.t64[0]; \ + } else { \ + t[0] = dfp.t64[HI_IDX]; \ + t[1] = dfp.t64[LO_IDX]; \ + } \ +} + +DFP_HELPER_SHIFT(dscli, 64, 1) +DFP_HELPER_SHIFT(dscliq, 128, 1) +DFP_HELPER_SHIFT(dscri, 64, 0) +DFP_HELPER_SHIFT(dscriq, 128, 0) |
