From: Jim Blandy <jimb@sourceware.org>
Date: Tue, 17 May 2005 01:47:16 +0000 (+0000)
Subject: * sid.scm (gen-ifetch): Require BITSIZE to be exactly the size
X-Git-Url: https://sourceware.org/git/?a=commitdiff_plain;h=1741d8b73175ad6017f1d9a77eab9dd7085c5e40;p=cgen.git

* sid.scm (gen-ifetch): Require BITSIZE to be exactly the size
fetched by one of our GETIMEM* methods.
* utils-gen.scm (-extract-chunk-specs): Always fetch full
base-insn-sized chunks.
---

diff --git a/ChangeLog b/ChangeLog
index b337c22..14890c4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2005-05-16  Jim Blandy  <jimb@redhat.com>
+
+	* sid.scm (gen-ifetch): Require BITSIZE to be exactly the size
+	fetched by one of our GETIMEM* methods.
+	* utils-gen.scm (-extract-chunk-specs): Always fetch full
+	base-insn-sized chunks.
+
 2005-05-10  Nick Clifton  <nickc@redhat.com>
 
 	* Update the address and phone number of the FSF organization in
diff --git a/sid.scm b/sid.scm
index dee51b7..e40d0d5 100644
--- a/sid.scm
+++ b/sid.scm
@@ -184,6 +184,13 @@
 ; Return C code to fetch a value from instruction memory.
 ; PC-VAR is the C expression containing the address of the start of the
 ; instruction.
+;
+; We don't bother trying to handle bitsizes that don't have a
+; corresponding GETIMEM method.  Doing so would require us to take
+; endianness into account just to ensure that the requested bits end
+; up at the proper place in the result.  It's easier just to make the
+; caller ask us for something we can do directly.
+;
 ; ??? Aligned/unaligned support?
 
 (define (gen-ifetch pc-var bitoffset bitsize)
@@ -191,7 +198,6 @@
 		 (case bitsize
 		   ((8) "UQI")
 		   ((16) "UHI")
-		   ((24) "USI")
 		   ((32) "USI")
 		   (else (error "bad bitsize argument to gen-ifetch" bitsize)))
 		 " (pc, "
diff --git a/utils-gen.scm b/utils-gen.scm
index 9d4c4ff..ba4777a 100644
--- a/utils-gen.scm
+++ b/utils-gen.scm
@@ -308,7 +308,12 @@
 	  (reverse! result)
 	  (loop (+ start chunk-length)
 		(- remaining chunk-length)
-		(cons (cons start (min chunk-length remaining))
+		; Always fetch full CHUNK-LENGTH-sized chunks here,
+		; even if we don't actually need that many bytes.
+		; gen-ifetch only handles "normal" fetch sizes,
+		; and -gen-extract-word already knows how to find what
+		; it needs if we give it too much.
+		(cons (cons start chunk-length)
 		      result)))))
 )