From be76ee56a89e72c0b87a605321bb1670e86f8220 Mon Sep 17 00:00:00 2001
From: mid-kid <esteve.varela@gmail.com>
Date: Sun, 25 Mar 2018 18:24:14 +0200
Subject: Organize the engine/ directory, director's cut

Cleaned up `engine/routines`, in favor of moving files into more
appropriate directories. predef-related routines are now in top-level
`engine`.
`rtc/delete_save_change_clock.asm` has been split into both
`menus/delete_save.asm` and `rtc/reset_password.asm`.

Made a new subdirectory:
* engine/math: Contains all generic math-related routines.
---
 engine/math/math.asm | 196 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 196 insertions(+)
 create mode 100755 engine/math/math.asm

(limited to 'engine/math/math.asm')

diff --git a/engine/math/math.asm b/engine/math/math.asm
new file mode 100755
index 000000000..0cd6b0b47
--- /dev/null
+++ b/engine/math/math.asm
@@ -0,0 +1,196 @@
+_Multiply:: ; 66de
+
+; hMultiplier is one byte.
+	ld a, 8
+	ld b, a
+
+	xor a
+	ld [hProduct], a
+	ld [hMathBuffer + 1], a
+	ld [hMathBuffer + 2], a
+	ld [hMathBuffer + 3], a
+	ld [hMathBuffer + 4], a
+
+
+.loop
+	ld a, [hMultiplier]
+	srl a
+	ld [hMultiplier], a
+	jr nc, .next
+
+	ld a, [hMathBuffer + 4]
+	ld c, a
+	ld a, [hMultiplicand + 2]
+	add c
+	ld [hMathBuffer + 4], a
+
+	ld a, [hMathBuffer + 3]
+	ld c, a
+	ld a, [hMultiplicand + 1]
+	adc c
+	ld [hMathBuffer + 3], a
+
+	ld a, [hMathBuffer + 2]
+	ld c, a
+	ld a, [hMultiplicand + 0]
+	adc c
+	ld [hMathBuffer + 2], a
+
+	ld a, [hMathBuffer + 1]
+	ld c, a
+	ld a, [hProduct]
+	adc c
+	ld [hMathBuffer + 1], a
+
+.next
+	dec b
+	jr z, .done
+
+
+; hMultiplicand <<= 1
+
+	ld a, [hMultiplicand + 2]
+	add a
+	ld [hMultiplicand + 2], a
+
+	ld a, [hMultiplicand + 1]
+	rla
+	ld [hMultiplicand + 1], a
+
+	ld a, [hMultiplicand + 0]
+	rla
+	ld [hMultiplicand + 0], a
+
+	ld a, [hProduct]
+	rla
+	ld [hProduct], a
+
+	jr .loop
+
+
+.done
+	ld a, [hMathBuffer + 4]
+	ld [hProduct + 3], a
+
+	ld a, [hMathBuffer + 3]
+	ld [hProduct + 2], a
+
+	ld a, [hMathBuffer + 2]
+	ld [hProduct + 1], a
+
+	ld a, [hMathBuffer + 1]
+	ld [hProduct + 0], a
+
+	ret
+; 673e
+
+
+_Divide:: ; 673e
+	xor a
+	ld [hMathBuffer + 0], a
+	ld [hMathBuffer + 1], a
+	ld [hMathBuffer + 2], a
+	ld [hMathBuffer + 3], a
+	ld [hMathBuffer + 4], a
+
+	ld a, 9
+	ld e, a
+
+.loop
+	ld a, [hMathBuffer + 0]
+	ld c, a
+	ld a, [hDividend + 1]
+	sub c
+	ld d, a
+
+	ld a, [hDivisor]
+	ld c, a
+	ld a, [hDividend + 0]
+	sbc c
+	jr c, .next
+
+	ld [hDividend + 0], a
+
+	ld a, d
+	ld [hDividend + 1], a
+
+	ld a, [hMathBuffer + 4]
+	inc a
+	ld [hMathBuffer + 4], a
+
+	jr .loop
+
+.next
+	ld a, b
+	cp 1
+	jr z, .done
+
+	ld a, [hMathBuffer + 4]
+	add a
+	ld [hMathBuffer + 4], a
+
+	ld a, [hMathBuffer + 3]
+	rla
+	ld [hMathBuffer + 3], a
+
+	ld a, [hMathBuffer + 2]
+	rla
+	ld [hMathBuffer + 2], a
+
+	ld a, [hMathBuffer + 1]
+	rla
+	ld [hMathBuffer + 1], a
+
+	dec e
+	jr nz, .next2
+
+	ld e, 8
+	ld a, [hMathBuffer + 0]
+	ld [hDivisor], a
+	xor a
+	ld [hMathBuffer + 0], a
+
+	ld a, [hDividend + 1]
+	ld [hDividend + 0], a
+
+	ld a, [hDividend + 2]
+	ld [hDividend + 1], a
+
+	ld a, [hDividend + 3]
+	ld [hDividend + 2], a
+
+.next2
+	ld a, e
+	cp 1
+	jr nz, .okay
+	dec b
+
+.okay
+	ld a, [hDivisor]
+	srl a
+	ld [hDivisor], a
+
+	ld a, [hMathBuffer + 0]
+	rr a
+	ld [hMathBuffer + 0], a
+
+	jr .loop
+
+.done
+	ld a, [hDividend + 1]
+	ld [hDivisor], a
+
+	ld a, [hMathBuffer + 4]
+	ld [hDividend + 3], a
+
+	ld a, [hMathBuffer + 3]
+	ld [hDividend + 2], a
+
+	ld a, [hMathBuffer + 2]
+	ld [hDividend + 1], a
+
+	ld a, [hMathBuffer + 1]
+	ld [hDividend + 0], a
+
+	ret
+; 67c1
-- 
cgit v1.2.3


From 81fff9bb80af3db0ee381c824261b8963e1cc221 Mon Sep 17 00:00:00 2001
From: mid-kid <esteve.varela@gmail.com>
Date: Sun, 1 Apr 2018 17:03:11 +0200
Subject: Fix file permissions

I have no idea why this was a thing (do people store this repo on FAT32
flash drives or something?), but quite a bit of files had a permission
of 755. This isn't really a problem, but it's inconsistent and weird.
---
 engine/math/math.asm | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 mode change 100755 => 100644 engine/math/math.asm

(limited to 'engine/math/math.asm')

diff --git a/engine/math/math.asm b/engine/math/math.asm
old mode 100755
new mode 100644
-- 
cgit v1.2.3