Add home/print_bcd.asm

4 files changed, 83 insertions, 67 deletions

diff --git a/constants/text_constants.asm b/constants/text_constants.asm
index ee558956..745fb52c 100644
--- a/constants/text_constants.asm
+++ b/constants/text_constants.asm
@@ -33,12 +33,12 @@ TEXTBOX_INNERY EQU TEXTBOX_Y + 2
 ; PrintNum bit flags
 	const_def 5
 	const PRINTNUM_MONEY_F        ; 5
-	const PRINTNUM_RIGHTALIGN_F   ; 6
+	const PRINTNUM_LEFTALIGN_F   ; 6
 	const PRINTNUM_LEADINGZEROS_F ; 7
 
 ; PrintNum arguments (see engine/math/print_num.asm)
 PRINTNUM_MONEY          EQU 1 << PRINTNUM_MONEY_F
-PRINTNUM_RIGHTALIGN     EQU 1 << PRINTNUM_RIGHTALIGN_F
+PRINTNUM_LEFTALIGN     EQU 1 << PRINTNUM_LEFTALIGN_F
 PRINTNUM_LEADINGZEROS   EQU 1 << PRINTNUM_LEADINGZEROS_F
 
 ; character sets (see charmap.asm)
diff --git a/home.asm b/home.asm
index f275dd3f..97b41248 100644
--- a/home.asm
+++ b/home.asm
@@ -264,70 +264,7 @@ INCLUDE "home/mon_stats.asm"
 INCLUDE "home/cry.asm"
 INCLUDE "home/print_level.asm"
 INCLUDE "home/mon_data.asm"
-
-PrintBCDNumber:: ; 3ade (0:3ade)
-	ld b, c
-	res 7, c
-	res 6, c
-	res 5, c
-	bit 5, b
-	jr z, .asm_3af0
-	bit 7, b
-	jr nz, .asm_3af0
-	ld [hl], $f0
-	inc hl
-.asm_3af0
-	ld a, [de]
-	swap a
-	call Function3b15
-	ld a, [de]
-	call Function3b15
-	inc de
-	dec c
-	jr nz, .asm_3af0
-	bit 7, b
-	jr z, .asm_3b14
-	bit 6, b
-	jr nz, .asm_3b07
-	dec hl
-.asm_3b07
-	bit 5, b
-	jr z, .asm_3b0e
-	ld [hl], $f0
-	inc hl
-.asm_3b0e
-	ld [hl], $f6
-	call PrintLetterDelay
-	inc hl
-.asm_3b14
-	ret
-
-Function3b15:: ; 3b15 (0:3b15)
-	and $f
-	and a
-	jr z, .asm_3b2f
-	bit 7, b
-	jr z, .asm_3b29
-	bit 5, b
-	jr z, .asm_3b27
-	ld [hl], $f0
-	inc hl
-	res 5, b
-.asm_3b27
-	res 7, b
-.asm_3b29
-	add $f6
-	ld [hli], a
-	jp PrintLetterDelay
-
-.asm_3b2f
-	bit 7, b
-	jr z, .asm_3b29
-	bit 6, b
-	ret nz
-	ld a, $7f
-	ld [hli], a
-	ret
+INCLUDE "home/print_bcd.asm"
 
 GetPartyParamLocation::
 	push bc
diff --git a/home/print_bcd.asm b/home/print_bcd.asm
new file mode 100755
index 00000000..9401b26f
--- /dev/null
+++ b/home/print_bcd.asm
@@ -0,0 +1,79 @@
+PrintBCDNumber::
+; function to print a BCD (Binary-coded decimal) number
+; de = address of BCD number
+; hl = destination address
+; c = flags and length
+; bit 7: if set, do not print leading zeroes
+;        if unset, print leading zeroes
+; bit 6: if set, left-align the string (do not pad empty digits with spaces)
+;        if unset, right-align the string
+; bit 5: if set, print currency symbol at the beginning of the string
+;        if unset, do not print the currency symbol
+; bits 0-4: length of BCD number in bytes
+; Note that bits 5 and 7 are modified during execution. The above reflects
+; their meaning at the beginning of the functions's execution.
+	ld b, c ; save flags in b
+	res PRINTNUM_LEADINGZEROS_F, c
+	res PRINTNUM_LEFTALIGN_F, c
+	res PRINTNUM_MONEY_F, c ; c now holds the length
+	bit PRINTNUM_MONEY_F, b
+	jr z, .loop
+	bit PRINTNUM_LEADINGZEROS_F, b
+	jr nz, .loop ; skip currency symbol
+	ld [hl], "¥"
+	inc hl
+.loop
+	ld a, [de]
+	swap a
+	call PrintBCDDigit ; print upper digit
+	ld a, [de]
+	call PrintBCDDigit ; print lower digit
+	inc de
+	dec c
+	jr nz, .loop
+	bit PRINTNUM_LEADINGZEROS_F, b
+	jr z, .done ; if so, we are done
+.numberEqualsZero ; if every digit of the BCD number is zero
+	bit PRINTNUM_LEFTALIGN_F, b
+	jr nz, .skipLeftAlignmentAdjustment
+	dec hl ; if the string is left-aligned, it needs to be moved back one space
+.skipLeftAlignmentAdjustment
+	bit PRINTNUM_MONEY_F, b
+	jr z, .skipCurrencySymbol
+	ld [hl], "¥" ; currency symbol
+	inc hl
+.skipCurrencySymbol
+	ld [hl], "0"
+	call PrintLetterDelay
+	inc hl
+.done
+	ret
+
+PrintBCDDigit::
+	and %00001111
+	and a
+	jr z, .zeroDigit
+.nonzeroDigit
+	bit PRINTNUM_LEADINGZEROS_F, b ; have any non-space characters been printed?
+	jr z, .outputDigit
+; if bit 7 is set, then no numbers have been printed yet
+	bit PRINTNUM_MONEY_F, b
+	jr z, .skipCurrencySymbol
+	ld [hl], "¥"
+	inc hl
+	res PRINTNUM_MONEY_F, b
+.skipCurrencySymbol
+	res PRINTNUM_LEADINGZEROS_F, b ; unset 7 to indicate that a nonzero digit has been reached
+.outputDigit
+	add "0"
+	ld [hli], a
+	jp PrintLetterDelay
+
+.zeroDigit
+	bit PRINTNUM_LEADINGZEROS_F, b ; either printing leading zeroes or already reached a nonzero digit?
+	jr z, .outputDigit ; if so, print a zero digit
+	bit PRINTNUM_LEFTALIGN_F, b
+	ret nz
+	ld a, " "
+	ld [hli], a ; if right-aligned, "print" a space by advancing the pointer
+	ret
\ No newline at end of file
diff --git a/home/print_level.asm b/home/print_level.asm
index dbe14f74..9a7258ed 100755
--- a/home/print_level.asm
+++ b/home/print_level.asm
@@ -24,5 +24,5 @@ PrintLevel_Force3Digits::
 Print8BitNumRightAlign::
 	ld [wDeciramBuffer], a
 	ld de, wDeciramBuffer
-	ld b, PRINTNUM_RIGHTALIGN | 1
+	ld b, PRINTNUM_LEFTALIGN | 1
 	jp PrintNum
\ No newline at end of file