fixup S" and LIT-STRING for forced NUL termination

[rrq/rrqforth.git] / adoc / p_0branch.adoc

diff --git a/adoc/p_0branch.adoc b/adoc/p_0branch.adoc
index 4f396c3b82e5d3f08b2f3f2a537f45d9827515d2..6488d62ab6c305c4c421abd782609db3eaeab75a 100644 (file)
--- a/adoc/p_0branch.adoc
+++ b/adoc/p_0branch.adoc
@@ -1,6 +1,6 @@
-// rrqforth.asm:       WORD p_zero_branch,'0BRANCH',fasm
+// contorl.asm:        WORD p_zero_branch,'0BRANCH',fasm
 
-anchor:p_zero_branch[]
+anchor:p_0branch[]
 
 === Word: 0BRANCH
 
@@ -10,7 +10,17 @@ 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, is 0 then the branch offset is
-added, and otherwise execution continues with the cell following the
-branch offset in the definition.
+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>>.