Rename stage 0 editor

5 files changed, 120 insertions, 0 deletions

diff --git a/octedit/Makefile b/octedit/Makefile
new file mode 100644
index 0000000..26601c8
--- /dev/null
+++ b/octedit/Makefile
@@ -0,0 +1,22 @@
+all: build
+
+build: octedit.uf2
+
+octedit.uf2: octedit.elf
+	../elf/elf2uf2 octedit.elf octedit.uf2
+
+objects = uart.o main.o octedit.o
+
+octedit.elf: $(objects)
+	arm-none-eabi-ld -T pico_persist.ld -o octedit.elf $(objects) ../setup/setup.so
+	./checksum_pico_elf.py octedit.elf
+
+$(objects): %.o: %.s
+	arm-none-eabi-as -o $@ $<
+
+clean:
+	rm octedit.elf octedit.uf2 *.o
+
+flash: octedit.uf2
+	[ -h /dev/disk/by-label/RPI-RP2 ] || sleep 3s
+	cat octedit.uf2 > /dev/disk/by-label/RPI-RP2
diff --git a/octedit/main.s b/octedit/main.s
new file mode 100644
index 0000000..6c471ec
--- /dev/null
+++ b/octedit/main.s
@@ -0,0 +1,18 @@
+.syntax unified
+.cpu cortex-m0plus
+.thumb
+
+.section .entry, "ax"
+
+.type main, %function
+.global main
+
+main:
+  bl start_xosc
+  bl setup_clocks
+  bl setup_gpio
+  bl setup_uart
+  b octedit
+
+.section .stage_2_crc
+.word 0x00000000
diff --git a/octedit/octedit.s b/octedit/octedit.s
new file mode 100644
index 0000000..9445fd8
--- /dev/null
+++ b/octedit/octedit.s
@@ -0,0 +1,34 @@
+.syntax unified
+.cpu cortex-m0plus
+.thumb
+
+.equ SRAM_BASE, 0x20000000
+
+.type octedit, %function
+.global octedit
+
+octedit:
+  ldr r6, =SRAM_BASE
+  adds r5, r6, 1
+10:
+  movs r4, 0
+20:
+  bl uart_recv
+  cmp r0, '\r
+  beq 30f
+  cmp r0, 'G
+  beq 40f
+  bl uart_send
+  subs r0, '0
+  lsls r4, 3
+  adds r4, r0
+  b 20b
+30:
+  bl uart_send
+  movs r0, '\n
+  bl uart_send
+  strh r4, [r6]
+  adds r6, 2
+  b 10b
+40:
+  bx r5
diff --git a/octedit/pico_persist.ld b/octedit/pico_persist.ld
new file mode 100644
index 0000000..9c37aba
--- /dev/null
+++ b/octedit/pico_persist.ld
@@ -0,0 +1,13 @@
+MEMORY {
+  FLASH(rx) : ORIGIN = 0x10000000, LENGTH = 2M
+  SRAM(rx) : ORIGIN = 0x20041f00, LENGTH = 256
+}
+
+SECTIONS {
+  .text : {
+    *(.entry);
+    *(.text);
+    . = 252;
+    *(.stage_2_crc);
+  } >SRAM AT>FLASH
+}
diff --git a/octedit/uart.s b/octedit/uart.s
new file mode 100644
index 0000000..e79cbdc
--- /dev/null
+++ b/octedit/uart.s
@@ -0,0 +1,33 @@
+.syntax unified
+.cpu cortex-m0plus
+.thumb
+
+.equ UART0_BASE, 0x40034000
+.equ UARTDR_OFST,     0x00
+.equ UARTFR_OFST,     0x18
+
+.type uart_send, %function
+.global uart_send
+
+uart_send:
+  ldr r1, =UART0_BASE
+  movs r3, 0b1 << 5 // TX FIFO full
+1:
+  ldr r2, [r1, UARTFR_OFST]
+  tst r2, r3
+  bne 1b
+  strb r0, [r1, UARTDR_OFST]
+  bx lr
+
+.type uart_recv, %function
+.global uart_recv
+
+uart_recv:
+  ldr r1, =UART0_BASE
+  movs r3, 0b1 << 4 // RX FIFO empty
+1:
+  ldr r2, [r1, UARTFR_OFST]
+  tst r2, r3
+  bne 1b
+  ldrb r0, [r1, UARTDR_OFST]
+  bx lr