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Merge u3.md changes from jfranklin9000

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Raymond Pasco 2015-10-18 16:41:44 -04:00
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Spec/u3.md
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@ -163,8 +163,8 @@ Regular symbols follow this pattern:
u3w[a-g] jets (retain, nock core) i/j/w.h j/[a-g]/*.c
Irregular symbols always start with `u3` and obey no other rules.
They're defined in `i/n/u.h`. Finally, `i/all.h` includes all
these headers (fast compilers, yay) and is all you need to
They're defined in `i/n/aliases.h`. Finally, `i/all.h` includes
all these headers (fast compilers, yay) and is all you need to
program in `u3`.
### u3: noun internals
@ -175,10 +175,10 @@ If your `u3_noun` is less than `(1 << 31)`, it's a direct atom.
Every unsigned integer between `0` and `0x7fffffff` inclusive is
its own noun.
If bit `31` is set in a `u3_noun`, bit `30` is always set - this
bit is reserved. Bit `29` is `1` if the noun is a cell, `0` if
it's an atom. Bits `28` through `0` are a word pointer into the
loom - see below. The structures are:
If bit `31` is set in a `u3_noun` and bit `30` is `1` the noun
is an indirect cell. If bit `31` is set and bit `30` is `0` the
noun is an indirect atom. Bits `29` through `0` are a word
pointer into the loom - see below. The structures are:
typedef struct {
c3_w mug_w;
@ -400,9 +400,10 @@ A "south" road is the other way around:
Legend: `-` is durable storage (heap); `+` is temporary storage
(stack); `~` is deep storage (immutable); `$` is the allocation
frame `#` is free memory.
frame; `#` is free memory.
Pointer restrictions: pointers stored in `+` can point anywhere.
Of course, pointing to `#` (free memory) would be a bug.
Pointers in `-` can only point to `-` or `~`; pointers in `~`
only point to `~`.