diff options
Diffstat (limited to 'riscv/decode.h')
| -rw-r--r-- | riscv/decode.h | 43 |
1 files changed, 27 insertions, 16 deletions
diff --git a/riscv/decode.h b/riscv/decode.h index 9278a35..327da6c 100644 --- a/riscv/decode.h +++ b/riscv/decode.h @@ -37,6 +37,7 @@ const int FPRID_BITS = 5; const int NFPR = 1 << FPRID_BITS; const int IMM_BITS = 12; +const int IMMLO_BITS = 5; const int TARGET_BITS = 25; const int SHAMT_BITS = 6; const int FUNCT_BITS = 3; @@ -83,10 +84,20 @@ const int JUMP_ALIGN_BITS = 1; // note: bit fields are in little-endian order struct itype_t { + unsigned rd : GPRID_BITS; + unsigned rs1 : GPRID_BITS; signed imm12 : IMM_BITS; unsigned funct : FUNCT_BITS; + unsigned opcode : OPCODE_BITS; +}; + +struct btype_t +{ + unsigned immlo : IMMLO_BITS; unsigned rs1 : GPRID_BITS; - unsigned rdi : GPRID_BITS; + unsigned rs2 : GPRID_BITS; + signed immhi : IMM_BITS-IMMLO_BITS; + unsigned funct : FUNCT_BITS; unsigned opcode : OPCODE_BITS; }; @@ -98,28 +109,28 @@ struct jtype_t struct rtype_t { - unsigned rdr : GPRID_BITS; - unsigned functr : FUNCTR_BITS; - unsigned funct : FUNCT_BITS; + unsigned rd : GPRID_BITS; unsigned rs1 : GPRID_BITS; unsigned rs2 : GPRID_BITS; + unsigned functr : FUNCTR_BITS; + unsigned funct : FUNCT_BITS; unsigned opcode : OPCODE_BITS; }; -struct btype_t +struct ltype_t { + unsigned rd : GPRID_BITS; unsigned bigimm : BIGIMM_BITS; - unsigned rdi : GPRID_BITS; unsigned opcode : OPCODE_BITS; }; struct ftype_t { - unsigned rdr : FPRID_BITS; - unsigned rs3 : FPRID_BITS; - unsigned ffunct : FFUNCT_BITS; + unsigned rd : FPRID_BITS; unsigned rs1 : FPRID_BITS; unsigned rs2 : FPRID_BITS; + unsigned rs3 : FPRID_BITS; + unsigned ffunct : FFUNCT_BITS; unsigned opcode : OPCODE_BITS; }; @@ -129,6 +140,7 @@ union insn_t jtype_t jtype; rtype_t rtype; btype_t btype; + ltype_t ltype; ftype_t ftype; uint32_t bits; }; @@ -160,21 +172,20 @@ private: // helpful macros, etc #define RS1 R[insn.rtype.rs1] #define RS2 R[insn.rtype.rs2] -#define RDR do_writeback(R,insn.rtype.rdr) -#define RDI do_writeback(R,insn.itype.rdi) +#define RD do_writeback(R,insn.rtype.rd) #define FRS1 FR[insn.ftype.rs1] #define FRS2 FR[insn.ftype.rs2] #define FRS3 FR[insn.ftype.rs3] -#define FRDR FR[insn.ftype.rdr] -#define FRDI FR[insn.itype.rdi] -#define BIGIMM insn.btype.bigimm +#define FRD FR[insn.ftype.rd] +#define BIGIMM insn.ltype.bigimm #define SIMM insn.itype.imm12 +#define BIMM ((signed)insn.btype.immlo | (insn.btype.immhi << IMMLO_BITS)) #define SHAMT (insn.itype.imm12 & 0x3F) #define SHAMTW (insn.itype.imm12 & 0x1F) #define TARGET insn.jtype.target -#define BRANCH_TARGET (npc + (SIMM << BRANCH_ALIGN_BITS)) +#define BRANCH_TARGET (npc + (BIMM << BRANCH_ALIGN_BITS)) #define JUMP_TARGET (npc + (TARGET << JUMP_ALIGN_BITS)) -#define RM ((insn.ftype.ffunct >> 1) & 3) +#define RM (insn.ftype.ffunct & 3) #define require_supervisor if(!(sr & SR_S)) throw trap_privileged_instruction #define require64 if(gprlen != 64) throw trap_illegal_instruction |