Log: conditional execution, heap full

1 files changed, 48 insertions, 1 deletions

diff --git a/log.md b/log.md
index 464de51..c0b6b10 100644
--- a/log.md
+++ b/log.md
@@ -146,7 +146,8 @@ Both?
 ### 2016-10-03
 
 Another **problem**: the Start rule `twice twice ((+) 1) 0` gives a
-segmentation fault. At some point it switches to ARM mode.
+segmentation fault. At some point it switches to ARM mode. This is probably
+something that should be tackled later on.
 
 **Yet another problem**: the Start rule `[]` segfaults. The issue turns out to
 be that for this rule, the node entry point `n1` is accidentally
@@ -154,3 +155,49 @@ halfword-aligned. Hence, its bit 1 is set. This bit is used to store if a node
 has been reduced to (r)nf yet (not sure if rnf or nf). Therefore, it is not
 evaluated to `[]` properly before printing it. The **solution** to this issue
 is to `.align` node entry points (cg: `d9c2a69`).
+
+**New problem**: conditional instructions don't have a preceding `IT`
+instruction. A minimal example (borrowing some functions from StdEnv) is
+`Start = 1 < 2`. It seems to be resolved quite easily by adding an `IT` block
+(cg `9496e96`).
+
+**Question**: it is unclear to me how the instructions for `IFSGE` and `IFSLT`
+work. They branch, rather than move (`cgarmwas.c`):
+
+```c
+case IFSGE:
+	w_as_set_float_condition_instruction (instruction,"bpl","bmi");
+```
+
+The generated code would then be something like:
+
+```armasm
+bpl	rx,#1
+bmi	rx,#0
+```
+
+but what the constants are for (and if this is valid syntax) is unclear to me.
+
+**Problem**: there is no `Heap full` message. This can be verified with:
+
+```clean
+fromto :: !Int !Int -> [Int]
+fromto a b
+| a > b     = []
+| otherwise = [a:fromto (a+1) b]
+
+length :: [a] -> Int
+length xs = len 0 xs
+where
+	len :: Int [a] -> Int
+	len i []     = i
+	len i [_:xs] = len (i+1) xs
+
+hd :: [a] -> a
+hd [x:_] = x
+
+Start = let xs = fromto 1 100 in (length xs, hd xs)
+```
+
+and running with `-h 1k`. The program segfaults rather than displaying a `Heap
+full` message.