From daa6847068e3ae9b0201187f7f619feb27229385 Mon Sep 17 00:00:00 2001
From: Mischa Poslawsky <wormy@shiar.org>
Date: Sat, 12 Feb 2000 10:42:12 +0100
Subject: [PATCH] worm 0.80.0212: link improvements

---
 worm.asm | 172 +++++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 161 insertions(+), 11 deletions(-)

diff --git a/worm.asm b/worm.asm
index 383bab2..6c84154 100644
--- a/worm.asm
+++ b/worm.asm
@@ -272,8 +272,14 @@ setscorelimit:
 
 linkmatch:
   call _clrWindow
+
+
+; in  a,(7)
+; and %11
+; cp  %11
   ld  a,WormVersion
-  call SendByte
+; jr  nz,host
+  call send
   jr  c,host
 
 client:
@@ -673,16 +679,18 @@ removewormloop:
 
   ;hl=ix+head
   pop de ;ix+tail
-  or  a
+  ld  a,(gameCar)
+  and _datamulti
+  jr  nz,safewormsizedone
+;  or  a
   sbc hl,de
   ld  a,l
   rr  h
   rra
   inc a
   ld  (ix+grow),a
+safewormsizedone:
 
-  ld  de,10
-  call DecScore
   ld  h,(ix+head+1)
   ld  l,(ix+head)
   ld  (ix+tail+1),h
@@ -703,6 +711,10 @@ thislevel =$+1
 
   inc (ix+died)
   dec (ix+lives)
+  push af
+  ld  de,10
+  call DecScore
+  pop af
   ret nz ;HandleWorm done
   ld  a,(gameCar)
   and _datalivel
@@ -1216,7 +1228,41 @@ CheckPixel: ;at bc in d
   dec d
   ret
 
-FindPixel: ;bc to ahl + de gone
+;------------------------------------------------------
+;  CLEM's FIND_PIXEL
+;  by Clem
+;
+;  131 cycles  28 bytes    (b,c) to hl:a  destroyes: none
+;------------------------------------------------------
+
+FindPixel:
+	ld h,ScrBuffer/$800
+	ld a,c
+	add a,a
+	add a,a
+	ld l,a    ;hl=$3f00+4*y
+	ld a,b
+	rra
+	add hl,hl
+	rra
+	add hl,hl ;hl=$fc00+16*y
+	add hl,hl
+	rra       ;a=x/8
+	or l
+	ld l,a
+	ld a,b
+	and 7
+	cpl
+	rlca
+	rlca
+	rlca
+	ld (FP_Bit),a
+	xor a
+FP_Bit =$+1
+	set 0,a
+	ret
+
+;FindPixel: ;bc to ahl + de gone
   push de
   push bc
   ld  a,b
@@ -1226,11 +1272,11 @@ FindPixel: ;bc to ahl + de gone
   ld  d,offsets_table/256
   ld  h,0
   ld  l,c
-  add hl,hl
-  add hl,hl
-  add hl,hl
-  add hl,hl
-  add hl,hl
+  add hl,hl ;2y
+  add hl,hl ;4y
+  add hl,hl ;8y
+  add hl,hl ;16y
+  add hl,hl ;32y
   ld  a,b
   and %11111000
   rra
@@ -1769,6 +1815,8 @@ boxloopx:
 ;-----------------------------
 ;----------- link ------------
 ;-----------------------------
+#ifdef 0
+TIMEOUT = $1200
 
 send:
   push af ;ld b,a
@@ -1802,6 +1850,7 @@ ReceiveByteCont:
 ReceiveByte:
   call LinkPrep
 ReceiveBits:
+ ld de,TIMEOUT
 WaitRecBit:
   call checklink
   jr  z,LinkFailed
@@ -1819,6 +1868,7 @@ ReceiveLow:
   ld  (AckBit),a
   ld  a,d
   out (7),a
+ ld de,TIMEOUT
 WaitAckRec:
   call checklink
   cp  0
@@ -1851,12 +1901,14 @@ sendbit:
   ld  a,D0hD1l
 sendselected:
   out (7),a
+ ld de,TIMEOUT
 waitacknowledge:
   call checklink
   jr  nz,waitacknowledge
 SendAcked:
   ld  a,D0hD1h
   out (7),a
+ ld de,TIMEOUT
 waitsendready:
   call checklink
   cp  %11
@@ -1878,6 +1930,11 @@ linkerror:
   jp  Exit
 
 checklink:
+ pop hl
+ dec de
+ ld a,d
+ or e
+ jr z,LinkFailed
   ld  a,$BF ;key
   call _readkeypad
   bit 6,a
@@ -1885,8 +1942,98 @@ checklink:
 
   in  a,(7)
   and %11
+ jp (hl)
+  ret
+
+_readkeypad:
+  out (1),a
+  in  a,(1)
+  push af
+  ld  a,%11111111
+  out (1),a
+  pop af
+  ret
+#endif
+
+send:
+SendByte:
+  in  a,(7)
+  and %11
+  jr  z,nolink
+  ld  b,8
+sendloop:
+  ld  de,$8000
+  rl  c
+  ld  a,%11010100
+  jr  nc,sendbit
+  ld  a,%11101000
+sendbit:
+  out (7),a
+sendwait1:
+  call checklink
+  in  a,(7)
+  and  %11
+  jr  nz,sendwait1
+  ld  a,%11000000
+  out (7),a
+sendwait2:
+  call checklink
+  in  a,(7)
+  and %11
+  cp  %11
+  jr  nz,sendwait2
+  djnz sendloop
+  xor a
+  ret
+timeout:
+  scf
+  ret
+
+
+receive:
+  in  a,(7)
+  and %11
+  jr  z,nolink
+  cp  %11
+  jr  z,receive
+  ld  b,8
+receiveloop:
+  ld  de,$8000
+receivewait1:
+  call checklink
+  in  a,(7)
+  and %11
+  cp  %11
+  jr  z,receivewait1
+  rra
+  rl  c
+  rra
+  ld  a,%11010100
+  jr  nc,receivebit
+  ld  a,%11101000
+receivebit:
+  out (7),a
+receivewait2:
+  call checklink
+  in  a,(7)
+  and %11
+  jr  z,receivewait2
+  ld  a,%11000000
+  out (7),a
+  djnz receiveloop
+  xor a
   ret
 
+checklink:
+  dec de
+  ld  a,d
+  or  e
+  jr  z,timeout
+  ld  a,$BF ;key
+  call _readkeypad
+  bit 6,a
+  jr  z,timeout
+  ret
 _readkeypad:
   out (1),a
   in  a,(1)
@@ -1895,6 +2042,8 @@ _readkeypad:
   out (1),a
   pop af
   ret
+nolink:
+  jp  Exit
 
 ;-----------------------------
 ;---------- levels -----------
@@ -2079,6 +2228,7 @@ HiScore:  .db 0
 gamesdata:
 
 _datalink  = %00000001
+_datamulti = %00000010
 _datalivel = %00000010 ;ix+lives=0 limit
 _datafoodl = %00000100 ;left=0 limit
 _datanextl = %00001000 ;next level if left=0
@@ -2147,7 +2297,7 @@ name    = 21  ;game
 Level =$+1
 DispBuffer =$+2 ;912 bytes
 
-ScrBuffer   = $8200 ;-$A1FF (32x256)
+ScrBuffer   = $8000 ;-$A1FF (32x256)
 SinCosTable = $A200 ;-$A300 (4x64)
 
 ;-----------------------------
-- 
2.30.0