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-rw-r--r--usr.bin/oemu/cpu.c157
-rw-r--r--usr.bin/oemu/include/oemu/cpu.h14
-rw-r--r--usr.bin/oemu/include/oemu/osmx64.h2
-rw-r--r--usr.bin/oemu/include/oemu/types.h3
4 files changed, 175 insertions, 1 deletions
diff --git a/usr.bin/oemu/cpu.c b/usr.bin/oemu/cpu.c
index 9b8c622..07ddc7b 100644
--- a/usr.bin/oemu/cpu.c
+++ b/usr.bin/oemu/cpu.c
@@ -123,6 +123,108 @@ cpu_add(struct oemu_cpu *cpu, inst_t *inst)
}
/*
+ * Decode the INST_SUB instruction
+ *
+ * @cpu: CPU that is executing
+ * @inst: Instruction dword
+ */
+static void
+cpu_sub(struct oemu_cpu *cpu, inst_t *inst)
+{
+ struct cpu_regs *regs = &cpu->regs;
+ imm_t imm;
+
+ if (inst->rd > NELEM(regs->xreg)) {
+ printf("bad register operand for 'sub'\n");
+ return;
+ }
+
+ imm = regs->xreg[inst->rd];
+ regs->xreg[inst->rd] -= inst->imm;
+ printf("%d - %d -> X%d, new=%d\n",
+ imm, inst->imm, inst->rd, regs->xreg[inst->rd]);
+}
+
+/*
+ * Decode the INST_MUL instruction
+ *
+ * @cpu: CPU that is executing
+ * @inst: Instruction dword
+ */
+static void
+cpu_mul(struct oemu_cpu *cpu, inst_t *inst)
+{
+ struct cpu_regs *regs = &cpu->regs;
+ imm_t imm;
+
+ if (inst->rd > NELEM(regs->xreg)) {
+ printf("bad register operand for 'mul'\n");
+ return;
+ }
+
+ imm = regs->xreg[inst->rd];
+ regs->xreg[inst->rd] *= inst->imm;
+ printf("%d * %d -> X%d, new=%d\n",
+ imm, inst->imm, inst->rd, regs->xreg[inst->rd]);
+}
+
+/*
+ * Decode the INST_DIV instruction
+ *
+ * @cpu: CPU that is executing
+ * @inst: Instruction dword
+ */
+static void
+cpu_div(struct oemu_cpu *cpu, inst_t *inst)
+{
+ struct cpu_regs *regs = &cpu->regs;
+ imm_t imm;
+
+ if (inst->rd > NELEM(regs->xreg)) {
+ printf("bad register operand for 'div'\n");
+ return;
+ }
+
+ imm = regs->xreg[inst->rd];
+ if (imm == 0) {
+ /* TODO: Some sort of interrupt */
+ printf("** DIVIDE BY ZERO **\n");
+ return;
+ }
+
+ regs->xreg[inst->rd] /= inst->imm;
+ printf("%d / %d -> X%d, new=%d\n",
+ imm, inst->imm, inst->rd, regs->xreg[inst->rd]);
+}
+
+/*
+ * 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
@@ -130,11 +232,46 @@ cpu_reset(struct oemu_cpu *cpu)
{
struct cpu_regs *regs;
+ /*
+ * When an OSMX64 processor first starts up, it will
+ * initially be executing in supervisor mode with all
+ * of its registeres initialized to zeros.
+ */
regs = &cpu->regs;
regs->ip = 0;
+ regs->sr_state = CPU_SRS_SV;
+ regs->blr = 0x0;
+ regs->ilr = 0x0;
memset(regs->xreg, 0x0, sizeof(regs->xreg));
}
+void
+cpu_regdump(struct oemu_cpu *cpu)
+{
+ struct cpu_regs *regs;
+
+ regs = &cpu->regs;
+ printf(
+ "X0=%p, X1=%p, X2=%p\n"
+ "X3=%p, X4=%p, X5=%p\n"
+ "X6=%p, X7=%p, X8=%p\n"
+ "X9=%p, X10=%p, X11=%p\n"
+ "X12=%p, X13=%p, X14=%p\n"
+ "X15=%p, IP=%p, SRS=%p\n"
+ "BLR=%p, ILR=%p\n",
+ regs->xreg[0], regs->xreg[1],
+ regs->xreg[2], regs->xreg[3],
+ regs->xreg[4], regs->xreg[5],
+ regs->xreg[6], regs->xreg[7],
+ regs->xreg[8], regs->xreg[9],
+ regs->xreg[10], regs->xreg[11],
+ regs->xreg[12], regs->xreg[13],
+ regs->xreg[14], regs->xreg[15],
+ regs->ip, regs->sr_state,
+ regs->blr, regs->ilr
+ );
+}
+
/*
* Main instruction execution loop.
*/
@@ -161,6 +298,24 @@ cpu_kick(struct oemu_cpu *cpu, struct sysmem *mem)
case INST_ADD:
cpu_add(cpu, inst);
break;
+ case INST_SUB:
+ cpu_sub(cpu, inst);
+ break;
+ case INST_MUL:
+ cpu_mul(cpu, inst);
+ break;
+ case INST_DIV:
+ cpu_div(cpu, inst);
+ break;
+ case INST_BR:
+ cpu_br(cpu, inst);
+ break;
+ }
+
+ /* Is this a halt instruction? */
+ if (inst->opcode == INST_HLT) {
+ printf("HALTED\n");
+ break;
}
if (regs->ip >= MEMORY_SIZE) {
@@ -169,4 +324,6 @@ cpu_kick(struct oemu_cpu *cpu, struct sysmem *mem)
regs->ip += sizeof(*inst);
}
+
+ cpu_regdump(cpu);
}
diff --git a/usr.bin/oemu/include/oemu/cpu.h b/usr.bin/oemu/include/oemu/cpu.h
index df4cc80..882fe93 100644
--- a/usr.bin/oemu/include/oemu/cpu.h
+++ b/usr.bin/oemu/include/oemu/cpu.h
@@ -31,6 +31,7 @@
#define _OEMU_CPU_H_
#include <sys/types.h>
+#include <sys/param.h>
#include <stdint.h>
#include <stddef.h>
#include <oemu/types.h>
@@ -38,6 +39,12 @@
#define MEMORY_SIZE 512
/*
+ * Processor state register
+ */
+#define CPU_SRS_SV BIT(1) /* Supervisor flag */
+#define CPU_SRS_CARRY BIT(2) /* Carry flag */
+
+/*
* System memory
*
* @mem: Data
@@ -53,16 +60,23 @@ struct sysmem {
*
* @xreg: X<n>
* @ip: Instruction pointer
+ * @sr_state: Processor state register
+ * @blr: Branch link register
+ * @ilr: Interrupt link register
*/
struct cpu_regs {
reg_t xreg[16];
reg_t ip;
+ reg_t sr_state;
+ reg_t blr;
+ reg_t ilr;
};
struct oemu_cpu {
struct cpu_regs regs;
};
+void cpu_regdump(struct oemu_cpu *cpu);
void cpu_reset(struct oemu_cpu *cpu);
void cpu_kick(struct oemu_cpu *cpu, struct sysmem *mem);
diff --git a/usr.bin/oemu/include/oemu/osmx64.h b/usr.bin/oemu/include/oemu/osmx64.h
index d7ea8b1..b1df5d3 100644
--- a/usr.bin/oemu/include/oemu/osmx64.h
+++ b/usr.bin/oemu/include/oemu/osmx64.h
@@ -47,6 +47,8 @@
#define INST_SLL 0x11 /* Shift left logical operation */
#define INST_SRL 0x12 /* Shift right logical operation */
#define INST_MOV_IMM 0x13 /* Data move operation from IMM */
+#define INST_HLT 0x14 /* Halt */
+#define INST_BR 0x15 /* Branch */
/* Registers */
#define REG_X0 0x00
diff --git a/usr.bin/oemu/include/oemu/types.h b/usr.bin/oemu/include/oemu/types.h
index 0769c84..caf6e9b 100644
--- a/usr.bin/oemu/include/oemu/types.h
+++ b/usr.bin/oemu/include/oemu/types.h
@@ -33,7 +33,8 @@
#include <sys/types.h>
typedef uint64_t reg_t;
-typedef uintptr_t paddr_t;
+typedef uintptr_t addr_t;
typedef uint16_t imm_t;
+typedef addr_t paddr_t;
#endif /* !_OEMU_TYPES_H_ */
generated by cgit v1.2.3 (git 2.39.1) at 2025-07-23 00:13:33 +0000