Implement shadow register set and related instructions rdprs, wrprs. Fix eret to update either status or sstatus according to current register set. eret also changes register set when needed.
Signed-off-by: Amir Gonnen <amir.gon...@neuroblade.ai> --- target/nios2/cpu.c | 1 + target/nios2/cpu.h | 47 ++++++++++++++++++++++++++++++++++++++-- target/nios2/helper.h | 3 +++ target/nios2/op_helper.c | 24 ++++++++++++++++++++ target/nios2/translate.c | 32 ++++++++++++++++++++++----- 5 files changed, 100 insertions(+), 7 deletions(-) diff --git a/target/nios2/cpu.c b/target/nios2/cpu.c index 4cade61e93..0886705818 100644 --- a/target/nios2/cpu.c +++ b/target/nios2/cpu.c @@ -54,6 +54,7 @@ static void nios2_cpu_reset(DeviceState *dev) ncc->parent_reset(dev); memset(env->regs, 0, sizeof(uint32_t) * NUM_CORE_REGS); + memset(env->shadow_regs, 0, sizeof(uint32_t) * NUM_REG_SETS * NUM_GP_REGS); env->regs[R_PC] = cpu->reset_addr; #if defined(CONFIG_USER_ONLY) diff --git a/target/nios2/cpu.h b/target/nios2/cpu.h index d2ba0c5bbd..1d3503825b 100644 --- a/target/nios2/cpu.h +++ b/target/nios2/cpu.h @@ -57,9 +57,14 @@ struct Nios2CPUClass { #define EXCEPTION_ADDRESS 0x00000004 #define FAST_TLB_MISS_ADDRESS 0x00000008 +#define NUM_GP_REGS 32 +#define NUM_CR_REGS 32 /* GP regs + CR regs + PC */ -#define NUM_CORE_REGS (32 + 32 + 1) +#define NUM_CORE_REGS (NUM_GP_REGS + NUM_CR_REGS + 1) + +/* 63 shadow register sets. 0 is the primary set */ +#define NUM_REG_SETS 64 /* General purpose register aliases */ #define R_ZERO 0 @@ -80,7 +85,7 @@ struct Nios2CPUClass { #define R_RA 31 /* Control register aliases */ -#define CR_BASE 32 +#define CR_BASE NUM_GP_REGS #define CR_STATUS (CR_BASE + 0) #define CR_STATUS_PIE (1 << 0) #define CR_STATUS_U (1 << 1) @@ -88,7 +93,9 @@ struct Nios2CPUClass { #define CR_STATUS_IH (1 << 3) #define CR_STATUS_IL (63 << 4) #define CR_STATUS_CRS (63 << 10) +#define CR_STATUS_CRS_OFFSET 10 #define CR_STATUS_PRS (63 << 16) +#define CR_STATUS_PRS_OFFSET 16 #define CR_STATUS_NMI (1 << 22) #define CR_STATUS_RSIE (1 << 23) #define CR_ESTATUS (CR_BASE + 1) @@ -131,6 +138,7 @@ struct Nios2CPUClass { /* Other registers */ #define R_PC 64 +#define R_SSTATUS 30 /* Exceptions */ #define EXCP_BREAK 0x1000 @@ -157,6 +165,7 @@ struct Nios2CPUClass { struct CPUNios2State { uint32_t regs[NUM_CORE_REGS]; + uint32_t shadow_regs[NUM_REG_SETS][NUM_GP_REGS]; #if !defined(CONFIG_USER_ONLY) Nios2MMU mmu; @@ -246,4 +255,38 @@ static inline void cpu_get_tb_cpu_state(CPUNios2State *env, target_ulong *pc, *flags = (env->regs[CR_STATUS] & (CR_STATUS_EH | CR_STATUS_U)); } +static inline uint32_t cpu_get_crs(const CPUNios2State *env) +{ + return (env->regs[CR_STATUS] & CR_STATUS_CRS) + >> CR_STATUS_CRS_OFFSET; +} + +static inline uint32_t cpu_get_prs(const CPUNios2State *env) +{ + return (env->regs[CR_STATUS] & CR_STATUS_PRS) + >> CR_STATUS_PRS_OFFSET; +} + +static inline void cpu_change_reg_set(CPUNios2State *env, uint32_t prev_set, + uint32_t new_set) +{ + if (new_set == prev_set) { + return; + } + memcpy(env->shadow_regs[prev_set], env->regs, + sizeof(uint32_t) * NUM_GP_REGS); + memcpy(env->regs, env->shadow_regs[new_set], + sizeof(uint32_t) * NUM_GP_REGS); + env->regs[CR_STATUS] = (env->regs[CR_STATUS] & (~CR_STATUS_PRS)) + | ((prev_set << CR_STATUS_PRS_OFFSET) & CR_STATUS_PRS); + env->regs[CR_STATUS] = (env->regs[CR_STATUS] & (~CR_STATUS_CRS)) + | ((new_set << CR_STATUS_CRS_OFFSET) & CR_STATUS_CRS); +} + +static inline void cpu_set_crs(CPUNios2State *env, uint32_t value) +{ + uint32_t crs = cpu_get_crs(env); + cpu_change_reg_set(env, crs, value); +} + #endif /* NIOS2_CPU_H */ diff --git a/target/nios2/helper.h b/target/nios2/helper.h index 6c8f0b5b35..3e5c016e9c 100644 --- a/target/nios2/helper.h +++ b/target/nios2/helper.h @@ -18,6 +18,9 @@ * <http://www.gnu.org/licenses/lgpl-2.1.html> */ +DEF_HELPER_2(eret, void, env, i32) +DEF_HELPER_3(wrprs, void, env, i32, i32) +DEF_HELPER_2(rdprs, i32, env, i32) DEF_HELPER_FLAGS_2(raise_exception, TCG_CALL_NO_WG, noreturn, env, i32) #if !defined(CONFIG_USER_ONLY) diff --git a/target/nios2/op_helper.c b/target/nios2/op_helper.c index a59003855a..5e4f7a47ae 100644 --- a/target/nios2/op_helper.c +++ b/target/nios2/op_helper.c @@ -59,3 +59,27 @@ void helper_raise_exception(CPUNios2State *env, uint32_t index) cs->exception_index = index; cpu_loop_exit(cs); } + +void helper_wrprs(CPUNios2State *env, uint32_t reg_index, uint32_t value) +{ + uint32_t prs = cpu_get_prs(env); + env->shadow_regs[prs][reg_index] = value; +} + +uint32_t helper_rdprs(CPUNios2State *env, uint32_t reg_index) +{ + uint32_t prs = cpu_get_prs(env); + return env->shadow_regs[prs][reg_index]; +} + +void helper_eret(CPUNios2State *env, uint32_t new_pc) +{ + uint32_t crs = cpu_get_crs(env); + if (crs == 0) { + env->regs[CR_STATUS] = env->regs[CR_ESTATUS]; + } else { + env->regs[CR_STATUS] = env->regs[R_SSTATUS]; + } + cpu_change_reg_set(env, crs, cpu_get_crs(env)); + env->regs[R_PC] = new_pc; +} diff --git a/target/nios2/translate.c b/target/nios2/translate.c index f9abc2fdd2..e22ab1996a 100644 --- a/target/nios2/translate.c +++ b/target/nios2/translate.c @@ -205,6 +205,19 @@ static void call(DisasContext *dc, uint32_t code, uint32_t flags) /* * I-Type instructions */ + +/* + * rB <- prs.rA + sigma(IMM16) + */ +static void rdprs(DisasContext *dc, uint32_t code, uint32_t flags) +{ + I_TYPE(instr, code); + TCGv t = tcg_temp_new(); + gen_helper_rdprs(t, cpu_env, tcg_const_i32(instr.a)); + tcg_gen_addi_tl(cpu_R[instr.b], t, instr.imm16.s); + tcg_temp_free(t); +} + /* Load instructions */ static void gen_ldx(DisasContext *dc, uint32_t code, uint32_t flags) { @@ -365,7 +378,7 @@ static const Nios2Instruction i_type_instructions[] = { INSTRUCTION_FLG(gen_stx, MO_SL), /* stwio */ INSTRUCTION_FLG(gen_bxx, TCG_COND_LTU), /* bltu */ INSTRUCTION_FLG(gen_ldx, MO_UL), /* ldwio */ - INSTRUCTION_UNIMPLEMENTED(), /* rdprs */ + INSTRUCTION(rdprs), /* rdprs */ INSTRUCTION_ILLEGAL(), INSTRUCTION_FLG(handle_r_type_instr, 0), /* R-Type */ INSTRUCTION_NOP(), /* flushd */ @@ -378,14 +391,23 @@ static const Nios2Instruction i_type_instructions[] = { /* * R-Type instructions */ + +/* + * prs.rC <- rA + */ +static void wrprs(DisasContext *dc, uint32_t code, uint32_t flags) +{ + R_TYPE(instr, code); + gen_helper_wrprs(cpu_env, tcg_const_i32(instr.c), cpu_R[instr.a]); +} + /* - * status <- estatus + * status <- CRS == 0? estatus: sstatus * PC <- ea */ static void eret(DisasContext *dc, uint32_t code, uint32_t flags) { - tcg_gen_mov_tl(cpu_R[CR_STATUS], cpu_R[CR_ESTATUS]); - tcg_gen_mov_tl(cpu_R[R_PC], cpu_R[R_EA]); + gen_helper_eret(cpu_env, cpu_R[R_EA]); dc->base.is_jmp = DISAS_JUMP; } @@ -672,7 +694,7 @@ static const Nios2Instruction r_type_instructions[] = { INSTRUCTION_ILLEGAL(), INSTRUCTION(slli), /* slli */ INSTRUCTION(sll), /* sll */ - INSTRUCTION_UNIMPLEMENTED(), /* wrprs */ + INSTRUCTION(wrprs), /* wrprs */ INSTRUCTION_ILLEGAL(), INSTRUCTION(or), /* or */ INSTRUCTION(mulxsu), /* mulxsu */ -- 2.25.1 The contents of this email message and any attachments are intended solely for the addressee(s) and may contain confidential and/or privileged information and may be legally protected from disclosure. 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