Hello World!

5 files changed, 53 insertions, 35 deletions

diff --git a/elf.py b/elf.py
index ae81253..a3379c5 100755
--- a/elf.py
+++ b/elf.py
@@ -29,7 +29,7 @@ def wi(num, size=2):
 def padto(offset, cursor):
     missing = offset - cursor
     if missing < 0:
-        raise ValueError("already past offset!")
+        raise ValueError("cursor {} already past offset {}!".format(cursor, offset))
     w(b'\x00' * missing)
     return offset
 
@@ -57,12 +57,13 @@ def write_elf_header(segments):
     c += wi(0x0)           # e_shstrndx
     return c
 
-def write_program_header(segment, c):
+def write_program_header(segment, c, start):
     align = 0x1000
-    offset = (1 + c // align) * align
+    offset = (1 + start // align) * align
+    segment['offset'] = offset
     start = segment['addr']
     size = len(segment['content'])
-    segment['offset'] = offset
+    flags = 5 if segment['name'] == "code" else 6
 
     if offset % align != start % align:
         print("{:02x} {:02x}".format(offset, offset % align))
@@ -75,7 +76,7 @@ def write_program_header(segment, c):
     c += wi(start, 4)  # p_paddr
     c += wi(size, 4)   # p_filesz
     c += wi(size, 4)   # p_memsz
-    c += wi(0x5, 4)    # p_flags, 0x5=rx, 0x6=rw
+    c += wi(flags, 4)    # p_flags, 0x5=rx, 0x6=rw
     c += wi(align, 4)  # p_align
     return c
 
@@ -100,8 +101,10 @@ if __name__ == "__main__":
     cursor = 0
 
     c = write_elf_header(segments)
+    segment_start = 0x1000
     for seg in segments:
-        c = write_program_header(seg, c)
+        c = write_program_header(seg, c, segment_start)
+        segment_start = seg['offset'] + len(seg['content'])
 
     for seg in segments:
         c = padto(seg['offset'], c)
diff --git a/format.py b/format.py
index 6a6a3b2..053e04e 100644
--- a/format.py
+++ b/format.py
@@ -96,10 +96,11 @@ def pack_b(instr):
     return [op, imm_11, imm_lo, sub, rs1, rs2, imm_md, imm_12]
 
 def format(iter):
+    segment = None
     for line in iter:
         line = subv.parse(line)
 
-        if line['type'] == 'instr':
+        if segment == 'code' and line['type'] == 'instr':
             instr = line['instr']
             op = instr[0]
             if len(op) != 2:
@@ -121,11 +122,15 @@ def format(iter):
                 out = pack_s(instr)
             elif format == 'j':
                 out = pack_j(instr)
+            elif format == 'b':
+                out = pack_b(instr)
             else:
                 raise NotImplementedError()
 
             yield subv.format_instr(out)
         else:
+            if line['type'] == 'segment':
+                segment = line['segment'][0]
             yield line['raw']
 
 if __name__ == '__main__':
diff --git a/pack.py b/pack.py
index f772de3..98d7d86 100644
--- a/pack.py
+++ b/pack.py
@@ -4,27 +4,30 @@ import bits
 
 def byteify(word):
     (val, size) = word
-    if size != 32:
-        raise ValueError("Expected 32-bit word")
+    if size % 8 != 0:
+        raise ValueError("Not byte aligned: {} bits".format(size))
 
-    b0 = bits.slice(word,  7,  0)
-    b1 = bits.slice(word, 15,  8)
-    b2 = bits.slice(word, 23, 16)
-    b3 = bits.slice(word, 31, 24)
-    return [b0[:1], b1[:1], b2[:1], b3[:1]]
+    out = []
+    for i in range(0, size, 8):
+        byte = bits.slice(word,  i+7,  i)
+        out.append(byte[:1])
+    return out
 
 def pack(iter):
+    segment = None
     for line in iter:
         line = subv.parse(line)
         if line['type'] == 'instr':
             fields = [bits.from_part(p) for p in line['instr']]
             total = bits.concat(*fields)
 
-            if total[1] != 32:
+            if segment == 'code' and total[1] != 32:
                 raise ValueError("instruction parts do not add up to 32 bit!")
 
             yield subv.format_instr(byteify(total))
         else:
+            if line['type'] == 'segment':
+                segment = line['segment'][0]
             yield line['raw']
 
 if __name__ == '__main__':
diff --git a/survey.py b/survey.py
index 23fac27..442ef11 100644
--- a/survey.py
+++ b/survey.py
@@ -24,7 +24,7 @@ def observe(part, rel_addr, map):
 
         mode, size, shift = tag_re.match(tag).groups()
         size = int(size)
-        shift = int(shift)
+        shift = int(shift) if shift else 0
 
         if mode == 'imm':
             addr = bits.u(addr, size)
diff --git a/test.subv b/test.subv
index f1c73fd..05cb8c1 100644
--- a/test.subv
+++ b/test.subv
@@ -2,23 +2,30 @@
 main:
   # load 0x10010000 (UART0) into t0
   37/lui 5/rd/t0 0x10010/imm20
-  # store 0x48 (H) in UART0+0
-  13/opi 0/subop/add 6/rd/t1 0/rs/x0 48/imm12
+
+  # x4 = &message
+  # . load high bits
+  37/lui 4/rd/x4 Message/20/imm32>>12
+  # . add low bits
+  13/opi 0/subop/add 4/rd/x4 4/rs/x4 Message/12/imm32
+print:loop:
+  # load unsigned byte at x4
+  03/load 4/subop/lbu 6/rd/t1 4/rs/x4 0/imm12
+  # break loop if zero
+  63/branch 0/subop/== 6/rs/t1 0/rs/x0 print:break/off13
+  # print char
   23/store 2/subop/word 5/rs/t0 6/rs/t1 0/off12
-  # store 0x65 (e) in UART0+0
-  13/opi 0/subop/add 6/rd/t1 0/rs/x0 65/imm12
-  23/store 2/subop/word 5/rs/t0 6/rs/t1 0/off12
-  # store 0x6c (l) in UART0+0
-  13/opi 0/subop/add 6/rd/t1 0/rs/x0 6c/imm12
-  23/store 2/subop/word 5/rs/t0 6/rs/t1 0/off12
-  # store 0x6c (l) in UART0+0
-  13/opi 0/subop/add 6/rd/t1 0/rs/x0 6c/imm12
-  23/store 2/subop/word 5/rs/t0 6/rs/t1 0/off12
-  # store 0x6f (o) in UART0+0
-  13/opi 0/subop/add 6/rd/t1 0/rs/x0 6f/imm12
-  23/store 2/subop/word 5/rs/t0 6/rs/t1 0/off12
-  # store 0x0a (\n) in UART0+0
-  13/opi 0/subop/add 6/rd/t1 0/rs/x0 0a/imm12
-  23/store 2/subop/word 5/rs/t0 6/rs/t1 0/off12
-  # jump back up to the top
-  6f/jal 0/rd/x0 main/off21
+  # increment x4
+  13/opi 0/subop/add 4/rd/x4 4/rs/x4 1/imm12
+  # jump back up
+  6f/jal 0/rd/x0 print:loop/off21
+print:break:
+
+loop:
+  # infinite loop
+  6f/jal 0/rd/x0 loop/off21
+
+== data 0x80001000
+Message:
+  # "Hello World\n\0"
+  48/8 65/8 6c/8 6c/8 6f/8 20/8 77/8 6f/8 72/8 6c/8 64/8 21/8 0a/8 00/8