From f64806dbd40b494f22612749a135385b47c0753a Mon Sep 17 00:00:00 2001
From: d6 <d_m@plastic-idolatry.com>
Date: Thu, 10 Feb 2022 01:40:48 -0500
Subject: [PATCH] early version of goto-line working

---
 femto.tal | 55 +++++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 47 insertions(+), 8 deletions(-)

diff --git a/femto.tal b/femto.tal
index 7f40a3a..0eb11ab 100644
--- a/femto.tal
+++ b/femto.tal
@@ -58,8 +58,6 @@
 |0100
     ;read-filename .Console/vector DEO2
 
-    ( ;demo-path ;open-file JSR2 )
-
     ( use this if hardcoding to 80x24 )
     ( ;setup-80x24 JSR2 )
 
@@ -244,6 +242,29 @@
     ;draw-all JSR2
     BRK
 
+@goto-line ( -> )
+    #0060 ;jump-to-line JSR2
+    ;draw-all JSR2 BRK
+
+@jump-to-line ( n* -> )
+    ;term/rows LDA2 #0002 DIV2 LTH2k ( n rows/2 n<rows/2? ) ,&early JCN
+    OVR2 SWP2 SUB2 ( n n-rows/2 )
+    ;buffer/line-count LDA2 ( n n-rows/2 lines )
+    ;term/rows LDA2 SUB2 ( n n-rows/2 lines-rows )
+    GTH2k ( n n-rows/2 lines-rows n-rows/2>lines-rows? )
+    ,&late JCN ( n n-rows/2 lines-rows )
+    POP2 ,&finish JMP
+    &early ( n rows/2 )
+        POP2 ,&finish JCN 
+    &late ( n n-rows/2 lines-rows )
+        NIP2 ,&finish JCN
+    &finish ( n o )
+        SUB2k STH2
+        ;abs-line JSR2 ;buffer/offset STA2
+        #00 ;cursor/col STA
+        POP2 STH2r NIP ;cursor/row STA
+        JMP2r
+
 ( TODO: M-v for page up and M-> for goto end )
 (       M-f and M-b for next/previous word )
 (       M-n and M-p for next/previous paragraph )
@@ -252,6 +273,7 @@
     #00 ;saw-esc STA
     .Console/read DEI LIT '< EQU ( M-< ) ;goto-start JCN2
     .Console/read DEI LIT '> EQU ( M-> ) ;goto-end JCN2
+    .Console/read DEI LIT 'g EQU ( M-g ) ;goto-line JCN2
     BRK
 
 ( TODO: C-g or C-h for help )
@@ -337,6 +359,19 @@
     INC2 INC2r ,&loop JMP
     &end POP2 STH2r JMP2r
 
+@abs-line ( y* -> s* )
+    #0000 SWP2 SUB2 STH2 ( [-y] )
+    ;buffer/data LDA2 ( addr )
+    &newline ( addr [-y] )
+          STH2kr ORA ,&loop JCN ,&done JMP
+    &loop ( addr [-y] )
+          LDAk #00 EQU ,&not-found JCN ( addr [-y] )
+          LDAk #0a EQU ,&found JCN ( addr [-y] )
+          INC2 ,&loop JMP ( addr+1 [-y] )
+    &found INC2 INC2r ( addr+1 [-y+1] ) ,&newline JMP
+    &done POP2r JMP2r
+    &not-found POP2 POP2r #0000 JMP2r
+
 ( line number relative to the offset, starting at 0 )
 @rel-line ( y^ -> s* )
     #00 SWP SUB STH ( [-y] )
@@ -435,13 +470,14 @@
     &do2 #000a ;mod-div2 JSR2 NIP ;emit-digit JSR2
     &do1                      NIP ;emit-digit JSR2 JMP2r
 
-@tmp [ &pos :tmp/data &data $100 ]
-@term [ &cols 0050 &rows 0018 ] ( 80x24 )
-
 @input-error "input 20 "error 00
-@demo-path "math32.tal 00
 
-( col is 0-79, row is 0-23 )
+@tmp [ &pos :tmp/data
+       &data $100 ]
+
+@term [ &cols 0050
+        &rows 0018 ]
+
 @cursor [ &col 00 &row 00 ]
 
 ( did we just see ESC? )
@@ -450,4 +486,7 @@
 ( |1ffc )
 ( offset is address of the first visible line )
 ( size is total size of data in bytes )
-@buffer [ &limit 0000 &offset :buffer/data &data $8000 ]
+@buffer [ &limit 0000
+          &offset :buffer/data
+          &line-count 0000
+          &data $8000 ]