diff options
| -rw-r--r-- | target/arm/cpu.h | 3 | ||||
| -rw-r--r-- | target/arm/translate-vfp.c.inc | 176 |
2 files changed, 168 insertions, 11 deletions
diff --git a/target/arm/cpu.h b/target/arm/cpu.h index 11400a9d24..ad8b80c667 100644 --- a/target/arm/cpu.h +++ b/target/arm/cpu.h @@ -1569,6 +1569,9 @@ enum arm_cpu_mode { #define ARM_VFP_FPINST 9 #define ARM_VFP_FPINST2 10 +/* QEMU-internal value meaning "FPSCR, but we care only about NZCV" */ +#define QEMU_VFP_FPSCR_NZCV 0xffff + /* iwMMXt coprocessor control registers. */ #define ARM_IWMMXT_wCID 0 #define ARM_IWMMXT_wCon 1 diff --git a/target/arm/translate-vfp.c.inc b/target/arm/translate-vfp.c.inc index e100182a32..7a0cbca664 100644 --- a/target/arm/translate-vfp.c.inc +++ b/target/arm/translate-vfp.c.inc @@ -607,29 +607,183 @@ static bool trans_VDUP(DisasContext *s, arg_VDUP *a) return true; } -static bool trans_VMSR_VMRS(DisasContext *s, arg_VMSR_VMRS *a) +/* + * M-profile provides two different sets of instructions that can + * access floating point system registers: VMSR/VMRS (which move + * to/from a general purpose register) and VLDR/VSTR sysreg (which + * move directly to/from memory). In some cases there are also side + * effects which must happen after any write to memory (which could + * cause an exception). So we implement the common logic for the + * sysreg access in gen_M_fp_sysreg_write() and gen_M_fp_sysreg_read(), + * which take pointers to callback functions which will perform the + * actual "read/write general purpose register" and "read/write + * memory" operations. + */ + +/* + * Emit code to store the sysreg to its final destination; frees the + * TCG temp 'value' it is passed. + */ +typedef void fp_sysreg_storefn(DisasContext *s, void *opaque, TCGv_i32 value); +/* + * Emit code to load the value to be copied to the sysreg; returns + * a new TCG temporary + */ +typedef TCGv_i32 fp_sysreg_loadfn(DisasContext *s, void *opaque); + +/* Common decode/access checks for fp sysreg read/write */ +typedef enum FPSysRegCheckResult { + FPSysRegCheckFailed, /* caller should return false */ + FPSysRegCheckDone, /* caller should return true */ + FPSysRegCheckContinue, /* caller should continue generating code */ +} FPSysRegCheckResult; + +static FPSysRegCheckResult fp_sysreg_checks(DisasContext *s, int regno) +{ + if (!dc_isar_feature(aa32_fpsp_v2, s)) { + return FPSysRegCheckFailed; + } + + switch (regno) { + case ARM_VFP_FPSCR: + case QEMU_VFP_FPSCR_NZCV: + break; + default: + return FPSysRegCheckFailed; + } + + if (!vfp_access_check(s)) { + return FPSysRegCheckDone; + } + + return FPSysRegCheckContinue; +} + +static bool gen_M_fp_sysreg_write(DisasContext *s, int regno, + + fp_sysreg_loadfn *loadfn, + void *opaque) { + /* Do a write to an M-profile floating point system register */ TCGv_i32 tmp; - bool ignore_vfp_enabled = false; - if (!dc_isar_feature(aa32_fpsp_v2, s)) { + switch (fp_sysreg_checks(s, regno)) { + case FPSysRegCheckFailed: return false; + case FPSysRegCheckDone: + return true; + case FPSysRegCheckContinue: + break; } - if (arm_dc_feature(s, ARM_FEATURE_M)) { + switch (regno) { + case ARM_VFP_FPSCR: + tmp = loadfn(s, opaque); + gen_helper_vfp_set_fpscr(cpu_env, tmp); + tcg_temp_free_i32(tmp); + gen_lookup_tb(s); + break; + default: + g_assert_not_reached(); + } + return true; +} + +static bool gen_M_fp_sysreg_read(DisasContext *s, int regno, + fp_sysreg_storefn *storefn, + void *opaque) +{ + /* Do a read from an M-profile floating point system register */ + TCGv_i32 tmp; + + switch (fp_sysreg_checks(s, regno)) { + case FPSysRegCheckFailed: + return false; + case FPSysRegCheckDone: + return true; + case FPSysRegCheckContinue: + break; + } + + switch (regno) { + case ARM_VFP_FPSCR: + tmp = tcg_temp_new_i32(); + gen_helper_vfp_get_fpscr(tmp, cpu_env); + storefn(s, opaque, tmp); + break; + case QEMU_VFP_FPSCR_NZCV: /* - * The only M-profile VFP vmrs/vmsr sysreg is FPSCR. - * Accesses to R15 are UNPREDICTABLE; we choose to undef. - * (FPSCR -> r15 is a special case which writes to the PSR flags.) + * Read just NZCV; this is a special case to avoid the + * helper call for the "VMRS to CPSR.NZCV" insn. */ - if (a->reg != ARM_VFP_FPSCR) { - return false; - } - if (a->rt == 15 && !a->l) { + tmp = load_cpu_field(vfp.xregs[ARM_VFP_FPSCR]); + tcg_gen_andi_i32(tmp, tmp, 0xf0000000); + storefn(s, opaque, tmp); + break; + default: + g_assert_not_reached(); + } + return true; +} + +static void fp_sysreg_to_gpr(DisasContext *s, void *opaque, TCGv_i32 value) +{ + arg_VMSR_VMRS *a = opaque; + + if (a->rt == 15) { + /* Set the 4 flag bits in the CPSR */ + gen_set_nzcv(value); + tcg_temp_free_i32(value); + } else { + store_reg(s, a->rt, value); + } +} + +static TCGv_i32 gpr_to_fp_sysreg(DisasContext *s, void *opaque) +{ + arg_VMSR_VMRS *a = opaque; + + return load_reg(s, a->rt); +} + +static bool gen_M_VMSR_VMRS(DisasContext *s, arg_VMSR_VMRS *a) +{ + /* + * Accesses to R15 are UNPREDICTABLE; we choose to undef. + * FPSCR -> r15 is a special case which writes to the PSR flags; + * set a->reg to a special value to tell gen_M_fp_sysreg_read() + * we only care about the top 4 bits of FPSCR there. + */ + if (a->rt == 15) { + if (a->l && a->reg == ARM_VFP_FPSCR) { + a->reg = QEMU_VFP_FPSCR_NZCV; + } else { return false; } } + if (a->l) { + /* VMRS, move FP system register to gp register */ + return gen_M_fp_sysreg_read(s, a->reg, fp_sysreg_to_gpr, a); + } else { + /* VMSR, move gp register to FP system register */ + return gen_M_fp_sysreg_write(s, a->reg, gpr_to_fp_sysreg, a); + } +} + +static bool trans_VMSR_VMRS(DisasContext *s, arg_VMSR_VMRS *a) +{ + TCGv_i32 tmp; + bool ignore_vfp_enabled = false; + + if (arm_dc_feature(s, ARM_FEATURE_M)) { + return gen_M_VMSR_VMRS(s, a); + } + + if (!dc_isar_feature(aa32_fpsp_v2, s)) { + return false; + } + switch (a->reg) { case ARM_VFP_FPSID: /* |