Support self-relative expressions in offsets and immediates

Handle, hopefully correctly, self-relative expressions (that is,
expressions of the form X - Y where Y is a symbol in the current
segment, possibly $ or $$) used as offsets or immediates, as opposed
to arguments to Dx statements (which have already been supported for a
while.)

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 50 insertions, 0 deletions

diff --git a/test/pcrel.asm b/test/pcrel.asm
new file mode 100644
index 00000000..239e8cb8
--- /dev/null
+++ b/test/pcrel.asm
@@ -0,0 +1,50 @@
+	bits 32
+foo:				; Backwards reference
+	mov eax,[foo - $]
+	mov ebx,[ebx + foo - $]
+	mov ecx,foo - $
+	mov edx,foo - bar
+
+	mov eax,[bar - $]
+	mov ebx,[ebx + bar - $]
+	mov ecx,bar - $
+	mov edx,bar - foo
+
+	mov eax,[baz - $]
+	mov ebx,[ebx + baz - $]
+	mov esi,[baz - bar]
+	mov ecx,baz - $
+	mov edx,baz - bar
+
+	bits 64
+	default rel
+
+	mov eax,[foo]
+	mov eax,[foo - $]
+	mov eax,[abs foo - $]
+	mov ebx,[ebx + foo - $]
+	mov ecx,foo - $
+	mov edx,foo - bar
+
+	mov eax,[bar]
+	mov eax,[bar - $]
+	mov eax,[abs bar - $]
+	mov ebx,[ebx + bar - $]
+	mov ecx,bar - $
+	mov edx,bar - foo
+
+	mov eax,[baz]
+	mov eax,[baz - $]
+	mov eax,[abs baz - $]
+	mov ebx,[ebx + baz - $]
+	mov esi,[baz - bar]
+	mov esi,[abs baz - bar]
+	mov ecx,baz - $
+	mov edx,baz - bar
+
+bar:				; Forwards reference
+	hlt
+
+	section ".data"
+baz:				; Other-segment reference
+	dd 0