avr: automatically generate interrupt vectors

tools/gen-device-avr.py

@@ -201,6 +201,42 @@ const (
                         out.write('\n')
         out.write(')\n')
 
+def writeAsm(outdir, device):
+    # The interrupt vector, which is hard to write directly in Go.
+    out = open(outdir + '/' + device.metadata['nameLower'] + '.s', 'w')
+    out.write('''\
+; Automatically generated file. DO NOT EDIT.
+; Generated by gen-device-avr.py from {file}, see {descriptorSource}
+
+; Avoid the need for repeated .weak and .set instructions.
+.macro IRQ handler
+    .weak  \\handler
+    .set   \\handler, __vector_default
+.endm
+
+; The interrupt vector of this device. Must be placed at address 0 by the linker.
+.section .vectors
+.global  __vectors
+'''.format(**device.metadata))
+    num = 0
+    for intr in device.interrupts:
+        if intr['index'] < num:
+            # Some devices have duplicate interrupts, probably for historical
+            # reasons.
+            continue
+        while intr['index'] > num:
+            out.write('    jmp __vector_default\n')
+            num += 1
+        num += 1
+        out.write('    jmp __vector_{name}\n'.format(**intr))
+
+    out.write('''
+    ; Define default implementations for interrupts, redirecting to
+    ; __vector_default when not implemented.
+''')
+    for intr in device.interrupts:
+        out.write('    IRQ __vector_{name}\n'.format(**intr))
+
 def writeLD(outdir, device):
     # Variables for the linker script.
     out = open(outdir + '/' + device.metadata['nameLower'] + '.ld', 'w')
@@ -220,6 +256,7 @@ def generate(indir, outdir):
         print(filepath)
         device = readATDF(filepath)
         writeGo(outdir, device)
+        writeAsm(outdir, device)
         writeLD(outdir, device)