Identify wLinkBattleRNPreamble

3 files changed, 30 insertions, 26 deletions

diff --git a/constants/serial_constants.asm b/constants/serial_constants.asm
index ddb6f4fd..d3bc5e60 100644
--- a/constants/serial_constants.asm
+++ b/constants/serial_constants.asm
@@ -29,6 +29,8 @@ SERIAL_NO_DATA_BYTE               EQU $fe
 SERIAL_PATCH_LIST_PART_TERMINATOR EQU $ff
 
 SERIAL_PREAMBLE_LENGTH EQU 6
+SERIAL_RN_PREAMBLE_LENGTH EQU 7
+SERIAL_RNS_LENGTH EQU 10
 
 ; timeout duration after exchanging a byte
 SERIAL_LINK_BYTE_TIMEOUT EQU $5000
diff --git a/engine/link/link.asm b/engine/link/link.asm
index d8526687..37338ea9 100644
--- a/engine/link/link.asm
+++ b/engine/link/link.asm
@@ -71,9 +71,9 @@ Gen2ToGen1LinkComms:
 	ldh [rIF], a
 	ld a, 1 << SERIAL
 	ldh [rIE], a
-	ld hl, wd0dc
+	ld hl, wLinkBattleRNPreamble
 	ld de, wEnemyMonSpecies
-	ld bc, $11
+	ld bc, SERIAL_RN_PREAMBLE_LENGTH + SERIAL_RNS_LENGTH
 	call Serial_ExchangeBytes
 	ld a, SERIAL_NO_DATA_BYTE
 	ld [de], a
@@ -85,7 +85,7 @@ Gen2ToGen1LinkComms:
 	ld [de], a
 	ld hl, wc508
 	ld de, wTrademons
-	ld bc, wTrademons - wc508
+	ld bc, 200
 	call Serial_ExchangeBytes
 	xor a
 	ldh [rIF], a
@@ -215,9 +215,9 @@ Gen2ToGen2LinkComms:
 	ldh [rIF], a
 	ld a, 1 << SERIAL
 	ldh [rIE], a
-	ld hl, wd0dc
+	ld hl, wLinkBattleRNPreamble
 	ld de, wEnemyMonSpecies
-	ld bc, $11
+	ld bc, SERIAL_RN_PREAMBLE_LENGTH + SERIAL_RNS_LENGTH
 	call Serial_ExchangeBytes
 	ld a, SERIAL_NO_DATA_BYTE
 	ld [de], a
@@ -229,7 +229,7 @@ Gen2ToGen2LinkComms:
 	ld [de], a
 	ld hl, wc508
 	ld de, wTrademons
-	ld bc, wTrademons - wc508
+	ld bc, 200
 	call Serial_ExchangeBytes
 	ld a, [wLinkMode]
 	cp LINK_TRADECENTER
@@ -502,36 +502,41 @@ ClearLinkData:
 	ret
 
 FixDataForLinkTransfer:
-	ld hl, wd0dc
+	ld hl, wLinkBattleRNPreamble
 	ld a, SERIAL_PREAMBLE_BYTE
-	ld b, wLinkBattleRNs - wd0dc
-.loop1
+	ld b, SERIAL_RN_PREAMBLE_LENGTH
+.preamble_loop
 	ld [hli], a
 	dec b
-	jr nz, .loop1
-	ld b, wTempEnemyMonSpecies - wLinkBattleRNs
-.loop2
+	jr nz, .preamble_loop
+
+	assert wLinkBattleRNPreamble + SERIAL_RN_PREAMBLE_LENGTH == wLinkBattleRNs
+	ld b, SERIAL_RNS_LENGTH
+.rn_loop
 	call Random
 	cp SERIAL_PREAMBLE_BYTE
-	jr nc, .loop2
+	jr nc, .rn_loop
 	ld [hli], a
 	dec b
-	jr nz, .loop2
+	jr nz, .rn_loop
+
 	ld hl, wc508
 	ld a, SERIAL_PREAMBLE_BYTE
 	ld [hli], a
 	ld [hli], a
 	ld [hli], a
-	ld b, $c8
+
+	ld b, 200
 	xor a
-.loop3
+.loop1
 	ld [hli], a
 	dec b
-	jr nz, .loop3
+	jr nz, .loop1
+
 	ld hl, wTimeCapsulePlayerData - 1 + PARTY_LENGTH
 	ld de, wc512
 	lb bc, 0, 0
-.loop4
+.loop2
 	inc c
 	ld a, c
 	cp SERIAL_PREAMBLE_BYTE
@@ -554,19 +559,19 @@ FixDataForLinkTransfer:
 	inc hl
 	ld a, [hl]
 	cp SERIAL_NO_DATA_BYTE
-	jr nz, .loop4
+	jr nz, .loop2
 	ld a, c
 	ld [de], a
 	inc de
 	ld [hl], SERIAL_PATCH_LIST_PART_TERMINATOR
-	jr .loop4
+	jr .loop2
 
 .next1
 	ld a, SERIAL_PATCH_LIST_PART_TERMINATOR
 	ld [de], a
 	inc de
 	lb bc, 1, 0
-	jr .loop4
+	jr .loop2
 
 .done
 	ld a, SERIAL_PATCH_LIST_PART_TERMINATOR
diff --git a/wram.asm b/wram.asm
index 1153b7db..73beea91 100644
--- a/wram.asm
+++ b/wram.asm
@@ -1934,7 +1934,8 @@ wEvolutionCanceled:: db
 NEXTU
 ; link
 	ds 9
-wd0dc:: ds 1
+wLinkBattleRNPreamble:: ds SERIAL_RN_PREAMBLE_LENGTH
+wLinkBattleRNs:: ds SERIAL_RNS_LENGTH
 
 NEXTU
 ; miscellaneous
@@ -1945,10 +1946,6 @@ wOtherDecoration::    db
 wCurEnemyItem:: db
 ENDU
 
-	ds 3
-
-wLinkBattleRNs:: ds 10
-
 wTempEnemyMonSpecies::  db
 wTempBattleMonSpecies:: db