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target/arm: Fix VPT advance when ECI is non-zero

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We were not paying attention to the ECI state when advancing the VPT
state.  Architecturally, VPT state advance happens for every beat
(see the pseudocode VPTAdvance()), so on every beat the 4 bits of
VPR.P0 corresponding to the current beat are inverted if required,
and at the end of beats 1 and 3 the VPR MASK fields are updated.
This means that if the ECI state says we should not be executing all
4 beats then we need to skip some of the updating of the VPR that we
currently do in mve_advance_vpt().

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Peter Maydell 2021-08-13 17:11:49 +01:00
parent e0d40070e1
commit e3152d02da
1 changed files with 17 additions and 7 deletions
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24
target/arm/mve_helper.c
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@ -110,6 +110,8 @@ static void mve_advance_vpt(CPUARMState *env)
/* Advance the VPT and ECI state if necessary */
uint32_t vpr = env->v7m.vpr;
unsigned mask01, mask23;
uint16_t inv_mask;
uint16_t eci_mask = mve_eci_mask(env);
if ((env->condexec_bits & 0xf) == 0) {
env->condexec_bits = (env->condexec_bits == (ECI_A0A1A2B0 << 4)) ?
@ -121,17 +123,25 @@ static void mve_advance_vpt(CPUARMState *env)
return;
}
/* Invert P0 bits if needed, but only for beats we actually executed */
mask01 = FIELD_EX32(vpr, V7M_VPR, MASK01);
mask23 = FIELD_EX32(vpr, V7M_VPR, MASK23);
if (mask01 > 8) {
/* high bit set, but not 0b1000: invert the relevant half of P0 */
vpr ^= 0xff;
/* Start by assuming we invert all bits corresponding to executed beats */
inv_mask = eci_mask;
if (mask01 <= 8) {
/* MASK01 says don't invert low half of P0 */
inv_mask &= ~0xff;
}
if (mask23 > 8) {
/* high bit set, but not 0b1000: invert the relevant half of P0 */
vpr ^= 0xff00;
if (mask23 <= 8) {
/* MASK23 says don't invert high half of P0 */
inv_mask &= ~0xff00;
}
vpr = FIELD_DP32(vpr, V7M_VPR, MASK01, mask01 << 1);
vpr ^= inv_mask;
/* Only update MASK01 if beat 1 executed */
if (eci_mask & 0xf0) {
vpr = FIELD_DP32(vpr, V7M_VPR, MASK01, mask01 << 1);
}
/* Beat 3 always executes, so update MASK23 */
vpr = FIELD_DP32(vpr, V7M_VPR, MASK23, mask23 << 1);
env->v7m.vpr = vpr;
}