From 99c7834fba4e5f204a82a1c456de2148b9595135 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Thu, 19 Nov 2020 21:56:04 +0000 Subject: [PATCH] hw/intc/armv7m_nvic: Update FPDSCR masking for v8.1M The FPDSCR register has a similar layout to the FPSCR. In v8.1M it gains new fields FZ16 (if half-precision floating point is supported) and LTPSIZE (always reads as 4). Update the reset value and the code that handles writes to this register accordingly. Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson Message-id: 20201119215617.29887-16-peter.maydell@linaro.org --- hw/intc/armv7m_nvic.c | 9 ++++++++- target/arm/cpu.c | 3 +++ target/arm/cpu.h | 5 +++++ 3 files changed, 16 insertions(+), 1 deletion(-) diff --git a/hw/intc/armv7m_nvic.c b/hw/intc/armv7m_nvic.c index 9628ce876e..be3bc1f1f4 100644 --- a/hw/intc/armv7m_nvic.c +++ b/hw/intc/armv7m_nvic.c @@ -2068,7 +2068,14 @@ static void nvic_writel(NVICState *s, uint32_t offset, uint32_t value, break; case 0xf3c: /* FPDSCR */ if (cpu_isar_feature(aa32_vfp_simd, cpu)) { - value &= 0x07c00000; + uint32_t mask = FPCR_AHP | FPCR_DN | FPCR_FZ | FPCR_RMODE_MASK; + if (cpu_isar_feature(any_fp16, cpu)) { + mask |= FPCR_FZ16; + } + value &= mask; + if (cpu_isar_feature(aa32_lob, cpu)) { + value |= 4 << FPCR_LTPSIZE_SHIFT; + } cpu->env.v7m.fpdscr[attrs.secure] = value; } break; diff --git a/target/arm/cpu.c b/target/arm/cpu.c index 40f3f798b2..d6188f6566 100644 --- a/target/arm/cpu.c +++ b/target/arm/cpu.c @@ -262,6 +262,9 @@ static void arm_cpu_reset(DeviceState *dev) * always reset to 4. */ env->v7m.ltpsize = 4; + /* The LTPSIZE field in FPDSCR is constant and reads as 4. */ + env->v7m.fpdscr[M_REG_NS] = 4 << FPCR_LTPSIZE_SHIFT; + env->v7m.fpdscr[M_REG_S] = 4 << FPCR_LTPSIZE_SHIFT; } if (arm_feature(env, ARM_FEATURE_M_SECURITY)) { diff --git a/target/arm/cpu.h b/target/arm/cpu.h index 04f6220b2f..47cb5032ce 100644 --- a/target/arm/cpu.h +++ b/target/arm/cpu.h @@ -1521,14 +1521,19 @@ void vfp_set_fpscr(CPUARMState *env, uint32_t val); #define FPCR_IXE (1 << 12) /* Inexact exception trap enable */ #define FPCR_IDE (1 << 15) /* Input Denormal exception trap enable */ #define FPCR_FZ16 (1 << 19) /* ARMv8.2+, FP16 flush-to-zero */ +#define FPCR_RMODE_MASK (3 << 22) /* Rounding mode */ #define FPCR_FZ (1 << 24) /* Flush-to-zero enable bit */ #define FPCR_DN (1 << 25) /* Default NaN enable bit */ +#define FPCR_AHP (1 << 26) /* Alternative half-precision */ #define FPCR_QC (1 << 27) /* Cumulative saturation bit */ #define FPCR_V (1 << 28) /* FP overflow flag */ #define FPCR_C (1 << 29) /* FP carry flag */ #define FPCR_Z (1 << 30) /* FP zero flag */ #define FPCR_N (1 << 31) /* FP negative flag */ +#define FPCR_LTPSIZE_SHIFT 16 /* LTPSIZE, M-profile only */ +#define FPCR_LTPSIZE_MASK (7 << FPCR_LTPSIZE_SHIFT) + #define FPCR_NZCV_MASK (FPCR_N | FPCR_Z | FPCR_C | FPCR_V) #define FPCR_NZCVQC_MASK (FPCR_NZCV_MASK | FPCR_QC)