From aa4191aec26d4c20a8e41865ac1a3e4527ed40c7 Mon Sep 17 00:00:00 2001
From: jeffman <jefferbrecht@gmail.com>
Date: Thu, 6 Dec 2018 23:05:00 -0500
Subject: [PATCH] bin_to_bcd can be called from C

Remove old cash window formatting code (we'll be rewriting it in C)
---
 compiled/ext.c    |  1 +
 compiled/vwf.h    |  1 +
 m2-formatting.asm | 80 +++--------------------------------------------
 3 files changed, 6 insertions(+), 76 deletions(-)

diff --git a/compiled/ext.c b/compiled/ext.c
index 8d206b3..99b091b 100644
--- a/compiled/ext.c
+++ b/compiled/ext.c
@@ -2,3 +2,4 @@ typedef unsigned char byte;
 
 void __attribute__((naked)) cpufastset(void *source, void *dest, int mode) {}
 byte* __attribute__((naked)) m2_strlookup(int *offset_table, byte *strings, int index) {}
+int __attribute__((naked)) bin_to_bcd(int value, int* digit_count) {}
diff --git a/compiled/vwf.h b/compiled/vwf.h
index 26bf625..dcb14e8 100644
--- a/compiled/vwf.h
+++ b/compiled/vwf.h
@@ -76,3 +76,4 @@ extern byte m12_other_str8[];
 
 extern void cpufastset(void *source, void *dest, int mode);
 extern byte* m2_strlookup(int *offset_table, byte *strings, int index);
+extern int bin_to_bcd(int value, int* digit_count);
diff --git a/m2-formatting.asm b/m2-formatting.asm
index 9c7461c..609dcac 100644
--- a/m2-formatting.asm
+++ b/m2-formatting.asm
@@ -3,14 +3,14 @@
 // int bin_to_bcd(int binary)
 // In:
 //    r0: binary number
+//    r1: out pointer; amount of digits used will be returned here
 // Out:
 //    r0: BCD-coded number
-//    r1: amount of digits used
 //==============================================================================
 
 bin_to_bcd:
 
-push    {r2-r7,lr}
+push    {r1-r7,lr}
 mov     r2,r8
 mov     r3,r9
 push    {r2-r3}
@@ -120,6 +120,8 @@ mov     r1,r3
 pop     {r2-r3}
 mov     r8,r2
 mov     r9,r3
+pop     {r2}
+str     r1,[r2]
 pop     {r2-r7,pc}
 
 
@@ -196,77 +198,3 @@ add     r1,r1,r4
 //--------------------------------
 mov     r0,r1
 pop     {r1-r4,pc}
-
-
-//==============================================================================
-// ushort format_cash(int amount, char* output, int digits)
-// In:
-//    r0: amount
-//    r1: output string
-//    r2: digits
-// Out:
-//    r0: = digits - (digits rendered) - 1
-//==============================================================================
-
-format_cash:
-
-push    {r1-r7,lr}
-mov     r4,r1
-mov     r6,r2
-
-//--------------------------------
-// Figure out how many digits we need
-bl      bin_to_bcd
-mov     r5,r1
-mov     r7,r1
-
-// The window is 56 pixels wide:
-// each digit uses 6 pixels, the 0x sign uses 6, and the
-// double-zero uses 8
-mov     r2,42 // = 56 - 6 - 8
-lsl     r3,r1,2
-add     r3,r3,r1
-add     r1,r1,r3 // r1 *= 6
-sub     r1,r2,r1 // r1 = 42 - r1
-
-// Store the control code to the output
-mov     r2,0x5F
-strb    r2,[r4,0]
-mov     r2,0xFF
-strb    r2,[r4,1]
-strb    r1,[r4,2]
-
-// Store the dollar sign
-mov     r2,0x54
-strb    r2,[r4,3]
-add     r4,r4,4
-
-// Store the digits to the output
-mov     r2,8
-sub     r2,r2,r5
-lsl     r2,r2,2
-lsl     r0,r2                // Now the number is pushed to the left of the register
-
-@@prev:
-lsr     r1,r0,28            // Get the left-most digit
-add     r1,0x60             // Integer-to-char
-strb    r1,[r4,0]
-add     r4,r4,1
-lsl     r0,r0,4
-sub     r5,r5,1
-bne     @@prev
-
-// Store the double-zero sign
-mov     r1,0x56
-strb    r1,[r4,0]
-
-// Store the end code
-mov     r1,0
-strb    r1,[r4,1]
-mov     r1,0xFF
-strb    r1,[r4,2]
-
-//--------------------------------
-sub     r5,r6,r7
-sub     r0,r5,1
-pop     {r1-r7,pc}