From b3f292a9881f19b465f2a20306e6a9d062432176 Mon Sep 17 00:00:00 2001
From: Clifford Wolf <clifford@clifford.at>
Date: Tue, 14 Aug 2018 13:49:08 +0200
Subject: [PATCH] Improve picosoc demo firmware, picosoc firmware build fixes

Signed-off-by: Clifford Wolf <clifford@clifford.at>
---
 picosoc/Makefile   |  4 ++--
 picosoc/firmware.c | 22 ++++++++------------
 picosoc/start.s    | 52 ++++++++++++++++++++++++++++++++++++++++++----
 3 files changed, 59 insertions(+), 19 deletions(-)

diff --git a/picosoc/Makefile b/picosoc/Makefile
index 3eacbcc..0faf167 100644
--- a/picosoc/Makefile
+++ b/picosoc/Makefile
@@ -39,10 +39,10 @@ firmware.elf: sections.lds start.s firmware.c
 	riscv32-unknown-elf-gcc -march=rv32imc -Wl,-Bstatic,-T,sections.lds,--strip-debug -ffreestanding -nostdlib -o firmware.elf start.s firmware.c
 
 firmware.hex: firmware.elf
-	riscv32-unknown-elf-objcopy -O verilog firmware.elf > firmware.hex
+	riscv32-unknown-elf-objcopy -O verilog firmware.elf firmware.hex
 
 firmware.bin: firmware.elf
-	riscv32-unknown-elf-objcopy -O binary firmware.elf > firmware.bin
+	riscv32-unknown-elf-objcopy -O binary firmware.elf firmware.bin
 
 # ---- Testbench for SPI Flash Model ----
 
diff --git a/picosoc/firmware.c b/picosoc/firmware.c
index 7e60932..6ff4d26 100644
--- a/picosoc/firmware.c
+++ b/picosoc/firmware.c
@@ -108,10 +108,11 @@ char getchar_prompt(char *prompt)
 	uint32_t cycles_begin, cycles_now, cycles;
 	__asm__ volatile ("rdcycle %0" : "=r"(cycles_begin));
 
+	reg_leds = ~0;
+
 	if (prompt)
 		print(prompt);
 
-	reg_leds = ~0;
 	while (c == -1) {
 		__asm__ volatile ("rdcycle %0" : "=r"(cycles_now));
 		cycles = cycles_now - cycles_begin;
@@ -123,6 +124,7 @@ char getchar_prompt(char *prompt)
 		}
 		c = reg_uart_data;
 	}
+
 	reg_leds = 0;
 	return c;
 }
@@ -340,22 +342,16 @@ void cmd_benchmark_all()
 
 // --------------------------------------------------------
 
-extern uint32_t _sidata, _sdata, _edata, _sbss, _ebss;
-
 void main()
-{	
-	// copy data section
-	for (uint32_t *src = &_sidata, *dest = &_sdata; dest < &_edata;) {
-        *dest++ = *src++;
-	}
-    // zero out .bss section
-    for (uint32_t *dest = &_sbss; dest < &_ebss;) {
-        *dest++ = 0;
-    }
-
+{
+	reg_leds = 31;
 	reg_uart_clkdiv = 104;
+	print("Booting..\n");
+
+	reg_leds = 63;
 	set_flash_qspi_flag();
 
+	reg_leds = 127;
 	while (getchar_prompt("Press ENTER to continue..\n") != '\r') { /* wait */ }
 
 	print("\n");
diff --git a/picosoc/start.s b/picosoc/start.s
index 5e43feb..74c5635 100644
--- a/picosoc/start.s
+++ b/picosoc/start.s
@@ -35,11 +35,55 @@ addi x29, zero, 0
 addi x30, zero, 0
 addi x31, zero, 0
 
-# zero initialize scratchpad memory
+# Update LEDs
+li a0, 0x03000000
+li a1, 1
+sw a1, 0(a0)
+
+# zero initialize entire scratchpad memory
+li a0, 0x00000000
 setmemloop:
-sw zero, 0(x1)
-addi x1, x1, 4
-blt x1, sp, setmemloop
+sw a0, 0(a0)
+addi a0, a0, 4
+blt a0, sp, setmemloop
+
+# Update LEDs
+li a0, 0x03000000
+li a1, 3
+sw a1, 0(a0)
+
+# copy data section
+la a0, _sidata
+la a1, _sdata
+la a2, _edata
+bge a1, a2, end_init_data
+loop_init_data:
+lw a3, 0(a0)
+sw a3, 0(a1)
+addi a0, a0, 4
+addi a1, a1, 4
+blt a1, a2, loop_init_data
+end_init_data:
+
+# Update LEDs
+li a0, 0x03000000
+li a1, 7
+sw a1, 0(a0)
+
+# zero-init bss section
+la a0, _sbss
+la a1, _ebss
+bge a0, a1, end_init_bss
+loop_init_bss:
+sw zero, 0(a0)
+addi a0, a0, 4
+blt a0, a1, loop_init_bss
+end_init_bss:
+
+# Update LEDs
+li a0, 0x03000000
+li a1, 15
+sw a1, 0(a0)
 
 # call main
 call main