X-Git-Url: https://git.rrq.au/?a=blobdiff_plain;f=control.asm;h=b6bfe0f005e964ce1773fa025d7d618e01ea95e4;hb=d5613f1ba2ae4065d60df8e768027f437f740a7f;hp=e4051d7ca3001a1d96f51356fbf124c6ba000007;hpb=d5a8f559318ac57934871a48e964bac18557b601;p=rrq%2Frrqforth.git

diff --git a/control.asm b/control.asm
index e4051d7..b6bfe0f 100644
--- a/control.asm
+++ b/control.asm
@@ -41,7 +41,7 @@ p_true_branch_SKIP:
 	;; This prepares for a subsequent THEN to resolve the
 	;; conditional branch length.
 	mov rax,qword [p_here_DFA]
-	mov qword [rax],p_zero_branch_DFA
+	mov qword [rax],p_zero_branch_CFA
 	mov qword [rax+8],0
 	add rax,16
 	mov qword [p_here_DFA],rax
@@ -65,7 +65,7 @@ p_true_branch_SKIP:
 	;; the pending (0BRANCH 0) distance to egin the "else-part" of
 	;; the conditional.
 	mov rax,qword [p_here_DFA]
-	mov qword [rax],p_branch_DFA
+	mov qword [rax],p_branch_CFA
 	mov qword [rax+8],0
 	add rax,16
 	mov qword [p_here_DFA],rax
@@ -84,16 +84,40 @@ p_true_branch_SKIP:
 	push qword 0
 	next
 	
+	WORD p_break,'BREAK',fasm,IMMEDIATE
+	;; ( 0 * -- 0 a * )
+	;; Lays out a (BRANCH 0) cell pair and marks the current
+	;; address for later resolution
+	mov rax,qword [p_here_DFA]
+	mov qword [rax],p_branch_CFA
+	mov qword [rax+8],0
+	add rax,16
+	mov qword [p_here_DFA],rax
+	jmp p_ifbreak_elevate
+
 	WORD p_ifbreak,'IFBREAK',fasm,IMMEDIATE
-	;; ( -- a )
+	;; ( 0 * -- 0 a * )
 	;; Lays out a (1BRANCH 0) cell pair and marks the current
 	;; address for later resolution
 	mov rax,qword [p_here_DFA]
-	mov qword [rax],p_true_branch_DFA
+	mov qword [rax],p_true_branch_CFA
 	mov qword [rax+8],0
 	add rax,16
 	mov qword [p_here_DFA],rax
-	push rax
+	;; Elevate stack entries until a 0 is found. This places the
+	;; IFBREAK pointer below any IF-THEN block pointers
+p_ifbreak_elevate:
+	sub rsp,8
+	mov rbx,rsp
+p_ifbreak_loop:
+	add rbx,8
+	cmp qword [rbx],0
+	je p_ifbreak_end
+	mov rcx,qword [rbx]
+	mov qword [rbx-8],rcx
+	jmp p_ifbreak_loop
+p_ifbreak_end:
+	mov qword [rbx-8],rax
 	next
 
 	WORD p_ifagain,'IFAGAIN',fasm,IMMEDIATE
@@ -101,7 +125,7 @@ p_true_branch_SKIP:
 	;; Lays out a (1BRANCH ?) cell pair to conditionally repeat
 	;; from the prior BEGIN.
 	mov rax,qword [p_here_DFA]
-	mov qword [rax],p_true_branch_DFA
+	mov qword [rax],p_true_branch_CFA
 	mov qword [rax+8],0
 	add rax,16
 	mov qword [p_here_DFA],rax
@@ -122,17 +146,18 @@ p_ifagain_resolve:
 	;; Resolves all open branches for the preceding BEGIN and
 	;; optional several IFBREAK
 	mov rax,rsp
+p_end_scan:
 	cmp qword [rax],0
 	je p_end_resolve
 	add rax,8
-	jmp p_end_DFA
+	jmp p_end_scan
 p_end_resolve:
 	mov rax,qword [rax+8] ; address of BEGIN
 p_end_next:
 	pop rbx
 	cmp rbx,0
 	je p_end_ending
-	mov rcx,rax
+	mov rcx,qword [p_here_DFA]
 	sub rcx,rbx
 	mov qword [rbx-8],rcx
 	jmp p_end_next