X-Git-Url: https://git.rrq.au/?a=blobdiff_plain;f=adoc%2Fp_0branch.adoc;h=6488d62ab6c305c4c421abd782609db3eaeab75a;hb=53f50810894e81457a75348b0565b4281d4762b4;hp=16c69c0249c115ab3cddd90a70a5b8f1b1107db7;hpb=b7da3f7bbd1cb10241163abdb950472e539e796d;p=rrq%2Frrqforth.git

diff --git a/adoc/p_0branch.adoc b/adoc/p_0branch.adoc
index 16c69c0..6488d62 100644
--- a/adoc/p_0branch.adoc
+++ b/adoc/p_0branch.adoc
@@ -1,9 +1,26 @@
-anchor:p_zero_branch[]
+// contorl.asm:	WORD p_zero_branch,'0BRANCH',fasm
 
-Word: 0BRANCH
--------------
+anchor:p_0branch[]
 
-----
-rrqforth.asm:	WORD p_zero_branch,'0BRANCH',fasm
-----
+=== Word: 0BRANCH
 
+....
+Data stack: ( v -- )
+....
+
+"0BRANCH" is a function word that implements execution conditional by
+means of optionally adding the subsequent branch offset, or not, to
+the point of execution. If the value, v, is 0 then the branch offset
+is added, and otherwise execution continues with the cell following
+the branch offset in the definition.
+
+Note that the branch offset is a byte count and each FORTH word of a
+definition take up a cell of 8 bytes. The offset is relative to the
+cell address immediately subsequent to the offset cell. In other
+words, offset 0 is not branching anywhere and an offset of -16 would
+make a tight loop back to the branch instruction itself. The latter
+would pull data stack values until and including the first non-zero
+value.
+
+See also <<p_1branch,1BRANCH>>, <<p_branch,BRANCH>>, <<p_if,IF>>,
+<<p_else,ELSE>>, <<p_ifbreak,IFBREAK>> and <<p_ifagain,IFAGAIN>>.