new ui, control panel kinda works, display works, framebuffer works, serial write works. widget for registers works. next is serial input and the editor

dsa_resources/serial.dsa

@@ -0,0 +1,63 @@
+// lib:
+// serial.dsa
+//
+// usage:
+//   include serial "<relative path>"
+//
+//   push (register containing address of string)
+//   call serial::print
+//
+//   push (register containing byte)
+//   call serial::print_byte
+
+dw uart: 0x40000
+
+// ------------------------------------------
+// transmit a single byte via sentinel protocol
+// expects: byte in rg0, trashes rg2, rg3, rg4, rg5
+_serial_send:
+    shl rg0, 16, rg2        // shift byte to bits [23:16]
+    lli 0x01, rg0
+    shl rg0, 24, rg0        // valid flag in bits [31:24]
+    or rg0, rg2, rg2        // rg2 = 0x01_XX_0000
+
+    ldw uart, rg5           // rg5 = 0x40000 (uart address, held for store)
+
+_serial_wait:
+    ldw rg5, rg0            // poll mem[0x40000]
+    shr rg0, 24, rg0
+    lli 0x01, rg3
+    ieq rg0, rg3, rg4
+    jnz rg4, _serial_wait   // loop while valid == 1
+
+    stw rg2, rg5            // mem[0x40000] = sentinel word
+    ret
+
+// ------------------------------------------
+// prints the null-terminated string at addr(arg[0])
+print: func
+    ldw bpr, rg0, 8         // load string address from arg
+
+_serial_print_loop:
+    ldb rg0, rg2            // load byte
+    ieq rg2, zero, rg4      // null terminator?
+    jnz rg4, _serial_end
+
+    push rg0                // save string pointer
+    mov rg2, rg0
+    call _serial_send
+    pop rg0
+
+    addi rg0, 1
+    jmp _serial_print_loop
+
+// ------------------------------------------
+// prints the last byte of arg[0]
+print_byte: func
+    ldw bpr, rg0, 8
+    call _serial_send
+    jmp _serial_end
+
+// ------------------------------------------
+_serial_end:
+    return