From 7d80fee5b9e663148ddee714e3b755a0af20508d Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Mon, 11 Apr 2011 16:26:16 +0100 Subject: [PATCH] target-arm: Handle UNDEF cases for Neon invalid modified-immediates For Neon "one register and a modified immediate value" forms, the combination op=1 cmode=1111 is unallocated and should UNDEF. All instructions of this form also UNDEF if Q == 1 and Vd<0> == 1. We also add a comment on the only UNPREDICTABLE in this space. Signed-off-by: Peter Maydell Signed-off-by: Aurelien Jarno --- target-arm/translate.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/target-arm/translate.c b/target-arm/translate.c index a86c54c564..0a9b3cf354 100644 --- a/target-arm/translate.c +++ b/target-arm/translate.c @@ -5084,11 +5084,18 @@ static int disas_neon_data_insn(CPUState * env, DisasContext *s, uint32_t insn) } } else { /* (insn & 0x00380080) == 0 */ int invert; + if (q && (rd & 1)) { + return 1; + } op = (insn >> 8) & 0xf; /* One register and immediate. */ imm = (u << 7) | ((insn >> 12) & 0x70) | (insn & 0xf); invert = (insn & (1 << 5)) != 0; + /* Note that op = 2,3,4,5,6,7,10,11,12,13 imm=0 is UNPREDICTABLE. + * We choose to not special-case this and will behave as if a + * valid constant encoding of 0 had been given. + */ switch (op) { case 0: case 1: /* no-op */ @@ -5120,6 +5127,9 @@ static int disas_neon_data_insn(CPUState * env, DisasContext *s, uint32_t insn) imm = ~imm; break; case 15: + if (invert) { + return 1; + } imm = ((imm & 0x80) << 24) | ((imm & 0x3f) << 19) | ((imm & 0x40) ? (0x1f << 25) : (1 << 30)); break; -- 2.11.4.GIT