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target-ppc: Introduce DFP Test Exponent

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Add emulation of the PowerPC Decimal Floating Point Test Exponent
instructions dtstex[q][.].

Signed-off-by: Tom Musta <tommusta@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
This commit is contained in:
Tom Musta 2014-04-21 15:55:08 -05:00 • committed by Alexander Graf
parent 1bf9c0e133
commit f3d2b0bce0
3 changed files with 38 additions and 0 deletions
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32
target-ppc/dfp_helper.c
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@ -504,3 +504,35 @@ uint32_t helper_##op(CPUPPCState *env, uint64_t *a, uint32_t dcm) \
DFP_HELPER_TSTDG(dtstdg, 64)
DFP_HELPER_TSTDG(dtstdgq, 128)
#define DFP_HELPER_TSTEX(op, size) \
uint32_t helper_##op(CPUPPCState *env, uint64_t *a, uint64_t *b) \
{ \
struct PPC_DFP dfp; \
int expa, expb, a_is_special, b_is_special; \
\
dfp_prepare_decimal##size(&dfp, a, b, env); \
\
expa = dfp.a.exponent; \
expb = dfp.b.exponent; \
a_is_special = decNumberIsSpecial(&dfp.a); \
b_is_special = decNumberIsSpecial(&dfp.b); \
\
if (a_is_special || b_is_special) { \
int atype = a_is_special ? (decNumberIsNaN(&dfp.a) ? 4 : 2) : 1; \
int btype = b_is_special ? (decNumberIsNaN(&dfp.b) ? 4 : 2) : 1; \
dfp.crbf = (atype ^ btype) ? 0x1 : 0x2; \
} else if (expa < expb) { \
dfp.crbf = 0x8; \
} else if (expa > expb) { \
dfp.crbf = 0x4; \
} else { \
dfp.crbf = 0x2; \
} \
\
dfp_set_FPCC_from_CRBF(&dfp); \
return dfp.crbf; \
}
DFP_HELPER_TSTEX(dtstex, 64)
DFP_HELPER_TSTEX(dtstexq, 128)