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target/arm: Implement MVE WLSTP insn

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Implement the MVE WLSTP insn; this is like the existing WLS insn,
except that it specifies a size value which is used to set
FPSCR.LTPSIZE.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210614151007.4545-8-peter.maydell@linaro.org
This commit is contained in:
Peter Maydell 2021-06-14 16:09:17 +01:00
parent 76c32d721d
commit 6822abfdf8
2 changed files with 42 additions and 3 deletions
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6
target/arm/t32.decode
View File

@ -672,8 +672,12 @@ BL 1111 0. .......... 11.1 ............ @branch24
%lob_imm 1:10 11:1 !function=times_2
DLS 1111 0 0000 100 rn:4 1110 0000 0000 0001
WLS 1111 0 0000 100 rn:4 1100 . .......... 1 imm=%lob_imm
WLS 1111 0 0000 100 rn:4 1100 . .......... 1 imm=%lob_imm size=4
{
LE 1111 0 0000 0 f:1 0 1111 1100 . .......... 1 imm=%lob_imm
# This is WLSTP
WLS 1111 0 0000 0 size:2 rn:4 1100 . .......... 1 imm=%lob_imm
}
LCTP 1111 0 0000 000 1111 1110 0000 0000 0001
]

37
target/arm/translate.c
View File

@ -8134,7 +8134,11 @@ static bool trans_WLS(DisasContext *s, arg_WLS *a)
return false;
}
if (a->rn == 13 || a->rn == 15) {
/* CONSTRAINED UNPREDICTABLE: we choose to UNDEF */
/*
* For WLSTP rn == 15 is a related encoding (LE); the
* other cases caught by this condition are all
* CONSTRAINED UNPREDICTABLE: we choose to UNDEF
*/
return false;
}
if (s->condexec_mask) {
@ -8147,10 +8151,41 @@ static bool trans_WLS(DisasContext *s, arg_WLS *a)
*/
return false;
}
if (a->size != 4) {
/* WLSTP */
if (!dc_isar_feature(aa32_mve, s)) {
return false;
}
/*
* We need to check that the FPU is enabled here, but mustn't
* call vfp_access_check() to do that because we don't want to
* do the lazy state preservation in the "loop count is zero" case.
* Do the check-and-raise-exception by hand.
*/
if (s->fp_excp_el) {
gen_exception_insn(s, s->pc_curr, EXCP_NOCP,
syn_uncategorized(), s->fp_excp_el);
return true;
}
}
nextlabel = gen_new_label();
tcg_gen_brcondi_i32(TCG_COND_EQ, cpu_R[a->rn], 0, nextlabel);
tmp = load_reg(s, a->rn);
store_reg(s, 14, tmp);
if (a->size != 4) {
/*
* WLSTP: set FPSCR.LTPSIZE. This requires that we do the
* lazy state preservation, new FP context creation, etc,
* that vfp_access_check() does. We know that the actual
* access check will succeed (ie it won't generate code that
* throws an exception) because we did that check by hand earlier.
*/
bool ok = vfp_access_check(s);
assert(ok);
tmp = tcg_const_i32(a->size);
store_cpu_field(tmp, v7m.ltpsize);
}
gen_jmp_tb(s, s->base.pc_next, 1);
gen_set_label(nextlabel);