diff options
Diffstat (limited to 'target/arm/helper.c')
| -rw-r--r-- | target/arm/helper.c | 26 |
1 files changed, 22 insertions, 4 deletions
diff --git a/target/arm/helper.c b/target/arm/helper.c index 8646a7a119..8cb7a9451c 100644 --- a/target/arm/helper.c +++ b/target/arm/helper.c @@ -8548,8 +8548,18 @@ uint32_t HELPER(v7m_mrs)(CPUARMState *env, uint32_t reg) } } -void HELPER(v7m_msr)(CPUARMState *env, uint32_t reg, uint32_t val) -{ +void HELPER(v7m_msr)(CPUARMState *env, uint32_t maskreg, uint32_t val) +{ + /* We're passed bits [11..0] of the instruction; extract + * SYSm and the mask bits. + * Invalid combinations of SYSm and mask are UNPREDICTABLE; + * we choose to treat them as if the mask bits were valid. + * NB that the pseudocode 'mask' variable is bits [11..10], + * whereas ours is [11..8]. + */ + uint32_t mask = extract32(maskreg, 8, 4); + uint32_t reg = extract32(maskreg, 0, 8); + if (arm_current_el(env) == 0 && reg > 7) { /* only xPSR sub-fields may be written by unprivileged */ return; @@ -8558,8 +8568,16 @@ void HELPER(v7m_msr)(CPUARMState *env, uint32_t reg, uint32_t val) switch (reg) { case 0 ... 7: /* xPSR sub-fields */ /* only APSR is actually writable */ - if (reg & 4) { - xpsr_write(env, val, 0xf8000000); /* APSR */ + if (!(reg & 4)) { + uint32_t apsrmask = 0; + + if (mask & 8) { + apsrmask |= 0xf8000000; /* APSR NZCVQ */ + } + if ((mask & 4) && arm_feature(env, ARM_FEATURE_THUMB_DSP)) { + apsrmask |= 0x000f0000; /* APSR GE[3:0] */ + } + xpsr_write(env, val, apsrmask); } break; case 8: /* MSP */ |