diff options
| author | Peter Maydell <peter.maydell@linaro.org> | 2020-06-16 10:32:25 +0100 |
|---|---|---|
| committer | Peter Maydell <peter.maydell@linaro.org> | 2020-06-16 10:32:25 +0100 |
| commit | b28be09570d0827969b62b8f82b0f720a9915427 (patch) | |
| tree | f9e7883067c6f21e1fe8f40b10ee3736a10e698a /target/arm/translate.c | |
| parent | 9593a3988c3e788790aa107d778386b09f456a6d (diff) | |
| download | qemu-b28be09570d0827969b62b8f82b0f720a9915427.zip | |
target/arm: Convert Neon 3-reg-diff prewidening ops to decodetree
Convert the "pre-widening" insns VADDL, VSUBL, VADDW and VSUBW
in the Neon 3-registers-different-lengths group to decodetree.
These insns work by widening one or both inputs to double their
size, performing an add or subtract at the doubled size and
then storing the double-size result.
As usual, rather than copying the loop of the original decoder
(which needs awkward code to avoid problems when source and
destination registers overlap) we just unroll the two passes.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Diffstat (limited to 'target/arm/translate.c')
| -rw-r--r-- | target/arm/translate.c | 16 |
1 files changed, 4 insertions, 12 deletions
diff --git a/target/arm/translate.c b/target/arm/translate.c index bcdfec34d2..9376534441 100644 --- a/target/arm/translate.c +++ b/target/arm/translate.c @@ -5241,7 +5241,6 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn) /* Three registers of different lengths. */ int src1_wide; int src2_wide; - int prewiden; /* undefreq: bit 0 : UNDEF if size == 0 * bit 1 : UNDEF if size == 1 * bit 2 : UNDEF if size == 2 @@ -5251,10 +5250,10 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn) int undefreq; /* prewiden, src1_wide, src2_wide, undefreq */ static const int neon_3reg_wide[16][4] = { - {1, 0, 0, 0}, /* VADDL */ - {1, 1, 0, 0}, /* VADDW */ - {1, 0, 0, 0}, /* VSUBL */ - {1, 1, 0, 0}, /* VSUBW */ + {0, 0, 0, 7}, /* VADDL: handled by decodetree */ + {0, 0, 0, 7}, /* VADDW: handled by decodetree */ + {0, 0, 0, 7}, /* VSUBL: handled by decodetree */ + {0, 0, 0, 7}, /* VSUBW: handled by decodetree */ {0, 1, 1, 0}, /* VADDHN */ {0, 0, 0, 0}, /* VABAL */ {0, 1, 1, 0}, /* VSUBHN */ @@ -5269,7 +5268,6 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn) {0, 0, 0, 7}, /* Reserved: always UNDEF */ }; - prewiden = neon_3reg_wide[op][0]; src1_wide = neon_3reg_wide[op][1]; src2_wide = neon_3reg_wide[op][2]; undefreq = neon_3reg_wide[op][3]; @@ -5322,9 +5320,6 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn) } else { tmp = neon_load_reg(rn, pass); } - if (prewiden) { - gen_neon_widen(cpu_V0, tmp, size, u); - } } if (src2_wide) { neon_load_reg64(cpu_V1, rm + pass); @@ -5335,9 +5330,6 @@ static int disas_neon_data_insn(DisasContext *s, uint32_t insn) } else { tmp2 = neon_load_reg(rm, pass); } - if (prewiden) { - gen_neon_widen(cpu_V1, tmp2, size, u); - } } switch (op) { case 0: case 1: case 4: /* VADDL, VADDW, VADDHN, VRADDHN */ |