From 2118e12769269464a0a4b2c79aa7939289bebeb1 Mon Sep 17 00:00:00 2001
From: Tobias Klauser <tklauser@distanz.ch>
Date: Fri, 19 Nov 2010 11:04:15 +0100
Subject: Simulator updates

---
 nios2.c | 121 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 112 insertions(+), 9 deletions(-)

(limited to 'nios2.c')

diff --git a/nios2.c b/nios2.c
index 87eb3f3..86dee5e 100644
--- a/nios2.c
+++ b/nios2.c
@@ -16,10 +16,34 @@
 
 void nios2_cpu_reset(struct nios2 *cpu)
 {
-	memset(cpu, 0x00, sizeof(struct nios2));
+	/* Reset registers */
+	memset(cpu->gp_regs, 0x00, NIOS2_GP_REG_COUNT * sizeof(uint32_t));
+	memset(cpu->ctrl_regs, 0x00, NIOS2_CTRL_REG_COUNT * sizeof(uint32_t));
+
+	cpu->pc = 0;
 	cpu->mode = NIOS2_SUPERVISOR_MODE;
 }
 
+void nios2_cpu_init(struct nios2 *cpu)
+{
+	/* Set PC to entry address of program */
+	cpu->pc = cpu->mem->image_base;
+}
+
+void nios2_cpu_inc_pc(struct nios2 *cpu)
+{
+	cpu->pc += 4;
+}
+
+void nios2_simulate(struct nios2 *cpu)
+{
+	/* Did anyone write to r0? */
+	if (cpu->gp_regs[zero]) {
+		warn("Written to r0\n");
+		cpu->gp_regs[zero] = 0;
+	}
+}
+
 bool nios2_in_user_mode(struct nios2 *cpu)
 {
 	if (!cpu->has_mmu)
@@ -35,21 +59,100 @@ bool nios2_in_supervisor_mode(struct nios2 *cpu)
 	return !nios2_in_user_mode(cpu);
 }
 
-uint32_t nios2_cpu_fetch_instr(struct nios2 *cpu, uint32_t *mem_base)
+void nios2_exception(struct nios2 *cpu, uint8_t cause)
 {
-	uint32_t instr = 0;
+	cpu->ctrl_regs[exception] = (cause << 2) & 0x7C;
+}
 
-	return instr;
+uint32_t nios2_fetch_instr(struct nios2 *cpu)
+{
+	struct memory *mem = cpu->mem;
+
+	return mem->base[cpu->pc / 4];
 }
 
-int nios2_cpu_execute_instr(struct nios2 *cpu, uint32_t instr)
+int nios2_execute_instr(struct nios2 *cpu, uint32_t instr)
 {
 	instruction_handler handle_instr = instruction_get_handler(instr);
 
-	if (unlikely(handle_instr == NULL)) {
-		err("Invalid instruction %08x\n", instr);
-		return -1;
-	}
+	if (unlikely(handle_instr == NULL))
+		return INSTR_ERR;
 
 	return handle_instr(cpu, instr);
 }
+
+static const char *nios2_gp_registers[] = {
+	"zero",
+	"at",
+	"r2",
+	"r3",
+	"r4",
+	"r5",
+	"r6",
+	"r7",
+	"r8",
+	"r9",
+	"r10",
+	"r11",
+	"r12",
+	"r13",
+	"r14",
+	"r15",
+	"r16",
+	"r17",
+	"r18",
+	"r19",
+	"r20",
+	"r21",
+	"r22",
+	"r23",
+	"et",
+	"bt",
+	"gp",
+	"sp",
+	"fp",
+	"ea",
+	"ba",
+	"ra",
+};
+
+static const char *nios2_ctrl_registers[] = {
+	"status",
+	"estatus",
+	"bstatus",
+	"ienable",
+	"ipending",
+	"cpuid",
+	"reserved",
+	"exception",
+	"pteaddr",
+	"tlbacc",
+	"tlbmisc",
+	"reserved",
+	"badaddr",
+	"config",
+	"mpubase",
+	"mpuacc"
+};
+
+void nios2_dump_registers(struct nios2 *cpu)
+{
+	unsigned int i;
+	uint32_t *gp_regs = cpu->gp_regs;
+	uint32_t *ctrl_regs = cpu->ctrl_regs;
+
+	info("General-purpose registers:\n");
+	for (i = 0; i < NIOS2_GP_REG_COUNT; i++) {
+		info("  %8s 0x%08x", nios2_gp_registers[i], gp_regs[i]);
+		if ((i + 1) % 4 == 0)
+			info("\n");
+	}
+
+	info("Control registers:\n");
+	for (i = 0; i < NIOS2_CTRL_REG_COUNT; i++) {
+		info("  %10s 0x%08x", nios2_ctrl_registers[i], ctrl_regs[i]);
+		if ((i + 1) % 4 == 0)
+			info("\n");
+	}
+
+}
-- 
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