From 1bb6ced04c424874e078097b4d125a93c2e01504 Mon Sep 17 00:00:00 2001
From: Adam Sampson <ats@offog.org>
Date: Mon, 23 Apr 2018 16:41:34 +0100
Subject: [PATCH] Don't split two-word directives across blocks.

When:

- MIDAS is writing a "standard data" block to a REL file;
- it wants to write a 76 (local-to-global/rename/expunge) directive,
  which needs two words of data;
- and there's only one word of space left in the block;

it wrote the first one to the current block, and the second word to the
start of the next block. STINK 1/201 doesn't understand this, and treats
the second word as codebits for the next block, misinterpreting the
directives for that block; this results in missing symbols or junk being
loaded into memory.

For other two-word directives, MIDAS sets the IRCONT flag for all words
except the last one, to prevent the block from being flushed until the
directive is complete. Do the same for 76 directives.

Also fix CNSTA, which unset IRCONT *after* its last word; this was
probably harmless because it will be the first directive in a block so
can't be split.
---
 src/mudsys/midas.324 | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/mudsys/midas.324 b/src/mudsys/midas.324
index fe652f92..7f80ec74 100644
--- a/src/mudsys/midas.324
+++ b/src/mudsys/midas.324
@@ -2998,12 +2998,14 @@ OUTDE1:	TLNE FF,FLPPSS
 PLOGLO:	SKIPGE CONTRL
 	 RET
 	PUSH P,A
+	TRO I,IRCONT	;Don't end block between the two words
 	PUSHJ P,PBITS7
 	MOVEI A,CLGLO
 	PUSHJ P,PBITS
 	TLO SYM,400000	;SAY THIS IS NEW STYLE RQ,
 	PUSHJ P,OUTSM0	;PUNCH "OLD NAME" = SYMTAB IDX,
 	TLC SYM,440000	;SAY MAKE GLOBAL, OUTPUT ACTUAL NAME OF SYM.
+	TRZ I,IRCONT
 	PUSHJ P,OUTSM
 	JRST POPAJ
 
@@ -3936,8 +3938,8 @@ CNSTA:	HRRZ T,PBCON
 	TLO A,100000	;RELOCATE
 	PUSHJ P,$OUTPT
 	HRRZ A,1(T)
-	PUSHJ P,$OUTPT	;OUTPUT VALUE, FIRST LOCATION IN AREA
 	TRZ I,IRCONT
+	PUSHJ P,$OUTPT	;OUTPUT VALUE, FIRST LOCATION IN AREA
 CNSTDA:	MOVSI A,CTDEF
 	IORM A,2(T)	;CALL IT DEFINED
 CNSTD:	TRNE FF,FRPSS2
@@ -6266,12 +6268,14 @@ IFN CREFSW,XCT CRFDEF
 	SKIPL CONTRL	;IF RELOCATABLE ANDLOCAL SYMBOL,
 	CAIL A,DEFGVR_-33.
 	 RET
+	TRO I,IRCONT	;Don't end block between the two words
 	PUSHJ P,PBITS7	;TELL STINK TO EXPUNGE SYM.
 	MOVEI A,CLGLO
 	PUSHJ P,PBITS
 	TLO SYM,400000	;SAY IS NEW TYPE RQ,
 	PUSHJ P,OUTSM0
 	MOVSI A,400000	;NEW NAME NULL => DELETE.
+	TRZ I,IRCONT
 	JRST $OUTPT
 
 ;EQUAL SYM1,SYM2	;DEFINE SYM1 SAME AS SYM2.