diff options
Diffstat (limited to 'instruction.c')
| -rw-r--r-- | instruction.c | 50 |
1 files changed, 39 insertions, 11 deletions
diff --git a/instruction.c b/instruction.c index 0ab99c8..6fd06dc 100644 --- a/instruction.c +++ b/instruction.c @@ -60,7 +60,7 @@ static int call(struct nios2 *cpu, uint32_t code) J_TYPE(instr, code); cpu->gp_regs[ra] = cpu->pc + 4; - cpu->pc = (instr->imm26 * 4) | (cpu->pc & 0xF0000000); + cpu->pc = (cpu->pc & 0xF0000000) | (instr->imm26 * 4); return PC_INC_BY_INSTR; } @@ -70,7 +70,7 @@ static int jmpi(struct nios2 *cpu, uint32_t code) { J_TYPE(instr, code); - cpu->pc = (instr->imm26 * 4) | (cpu->pc & 0xF0000000); + cpu->pc = (cpu->pc & 0xF0000000) | (instr->imm26 * 4); return PC_INC_BY_INSTR; } @@ -87,7 +87,7 @@ static int ldbu(struct nios2 *cpu, uint32_t code) uint32_t addr = gp_regs[instr->a] + (int16_t) instr->imm16; uint8_t byte; - if (nios2_load_byte(cpu, addr, &byte)) + if (nios2_load(cpu, addr, &byte, 1)) return INSTR_ERR; gp_regs[instr->b] = (uint32_t) byte; @@ -113,8 +113,9 @@ static int stb(struct nios2 *cpu, uint32_t code) I_TYPE(instr, code); uint32_t *gp_regs = cpu->gp_regs; uint32_t addr = gp_regs[instr->a] + (int16_t) instr->imm16; + uint8_t data = gp_regs[instr->b] & 0xFF; - if (nios2_store_byte(cpu, addr, gp_regs[instr->b] & 0xFF)) + if (nios2_store(cpu, addr, &data, 1)) return INSTR_ERR; return PC_INC_NORMAL; @@ -138,7 +139,7 @@ static int ldb(struct nios2 *cpu, uint32_t code) uint32_t addr = gp_regs[instr->a] + (int16_t) instr->imm16; uint8_t byte; - if (nios2_load_byte(cpu, addr, &byte)) + if (nios2_load(cpu, addr, &byte, 1)) return INSTR_ERR; gp_regs[instr->b] = (int32_t) byte; @@ -146,10 +147,37 @@ static int ldb(struct nios2 *cpu, uint32_t code) return PC_INC_NORMAL; } -/* */ -static int ldhu(struct nios2 *cpu __unused, uint32_t code __unused) +/* + * if ((signed) rA >= (signed) @(IMM16)) + * rB <- 1 + * else + * rB <- 0 + */ +static int cmpgei(struct nios2 *cpu, uint32_t code) { - /* TODO */ + I_TYPE(instr, code); + uint32_t *gp_regs = cpu->gp_regs; + + if ((int32_t) gp_regs[instr->a] >= (int32_t) ((int16_t) instr->imm16)) + gp_regs[instr->b] = 1; + else + gp_regs[instr->b] = 0; + + return PC_INC_NORMAL; +} + +/* rB <- 0x0000 : Mem16[rA + @IMM16)] */ +static int ldhu(struct nios2 *cpu, uint32_t code) +{ + I_TYPE(instr, code); + uint32_t *gp_regs = cpu->gp_regs; + uint32_t addr = gp_regs[instr->a] + (int16_t) instr->imm16; + uint16_t halfword; + + if (nios2_load(cpu, addr, &halfword, 2)) + return INSTR_ERR; + + gp_regs[instr->b] = (int32_t) halfword; return PC_INC_NORMAL; } @@ -199,7 +227,7 @@ static int ldh(struct nios2 *cpu __unused, uint32_t code __unused) } /* - * if ((signed) rA < (signed) @(IMM16) + * if ((signed) rA < (signed) @(IMM16)) * rB <- 1 * else * rB <- 0 @@ -268,7 +296,7 @@ static int ldw(struct nios2 *cpu, uint32_t code) uint32_t *gp_regs = cpu->gp_regs; uint32_t addr = gp_regs[instr->a] + (int16_t) instr->imm16; - if (nios2_load_word(cpu, addr, &gp_regs[instr->b])) + if (nios2_load(cpu, addr, &gp_regs[instr->b], 4)) return INSTR_ERR; return PC_INC_NORMAL; @@ -409,7 +437,7 @@ static struct instruction i_type_instructions[I_TYPE_COUNT] = { [STB] = INSTRUCTION(stb), [BR] = INSTRUCTION(br), [LDB] = INSTRUCTION(ldb), - [CMPGEI] = INSTRUCTION_UNIMPLEMENTED(cmpgei), + [CMPGEI] = INSTRUCTION(cmpgei), [LDHU] = INSTRUCTION(ldhu), [ANDI] = INSTRUCTION(andi), [STH] = INSTRUCTION(sth), |