diff options
Diffstat (limited to 'usr.bin/oemu/cpu.c')
| -rw-r--r-- | usr.bin/oemu/cpu.c | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/usr.bin/oemu/cpu.c b/usr.bin/oemu/cpu.c index 418febb..07ddc7b 100644 --- a/usr.bin/oemu/cpu.c +++ b/usr.bin/oemu/cpu.c @@ -198,6 +198,33 @@ cpu_div(struct oemu_cpu *cpu, inst_t *inst) } /* + * Decode the INST_DIV instruction + */ +static void +cpu_br(struct oemu_cpu *cpu, inst_t *inst) +{ + struct cpu_regs *regs = &cpu->regs; + imm_t imm; + addr_t br_to; + + if (inst->rd > NELEM(regs->xreg)) { + printf("bad register operand for 'br'\n"); + return; + } + + /* + * If we are branching to the reset vector, might + * as well reset all state. + */ + br_to = regs->xreg[inst->rd]; + if (br_to == 0) { + cpu_reset(cpu); + } + + regs->ip = br_to; +} + +/* * Reset a CPU to a default state */ void @@ -280,6 +307,9 @@ cpu_kick(struct oemu_cpu *cpu, struct sysmem *mem) case INST_DIV: cpu_div(cpu, inst); break; + case INST_BR: + cpu_br(cpu, inst); + break; } /* Is this a halt instruction? */ |