code shrinkage

2 files changed, 82 insertions, 22 deletions

diff --git a/README.txt b/README.txt
index e361781..8bf0349 100644
--- a/README.txt
+++ b/README.txt
@@ -121,10 +121,11 @@ arcade game).
 
 Bugs! At least these:
 
-- When exiting to DOS and reloading, the title screen graphics are
-  messed up. The playtester who reported this was running on real
-  hardware (not an emulator). I can't see how this is happening, but I
-  expect it's related to this:
+- Semi-fixed: When exiting to DOS and reloading, the title screen
+  graphics are messed up. The playtester who reported this was running
+  on real hardware (not an emulator). Getting the BSS below $9000 seems
+  to have fixed it. I can't see how this is happening, but I expect it's
+  related to this:
 
 - The BSS can overlap the start of the title screen (it's very close
   anyway). Consequences: There is a momentary graphics glitch when the
@@ -178,7 +179,9 @@ Bugs! At least these:
 - After a fight, "Arriving at Manila" or such would sometimes appears on the
   fight screen without clearing it first (if you ran away, you can still
   see ships). I *think* this is fixed, but I don't understand what caused
-  it so I'm leaving it in this list in case I'm wrong.
+  it so I'm leaving it in this list in case I'm wrong.... and I'm wrong,
+  because it just happened to me again. sea_battle() is returning something
+  unexpected, but how?
 
 Differences between the Apple II original and Linux port:
 
@@ -252,6 +255,22 @@ Other things that need doing to the code:
 
 - Decide what to do about integer overflow. Possibilities:
 
+  - This one seems like the best solution to me. The rest of the
+    stuff listed here is left for reference (for now). Here we go: Keep
+    using unsigned long for cash and debt, and use a ROM float for the
+    bank only. If you try to make a sale, borrow from wu, or withdraw an
+    amount that would overflow 32-bit cash, "Taipan, you cannot carry so
+    much cash! Your ship would sink under the weight of your riches!". If
+    pirate booty would overflow, don't award it. If debt interest would
+    result in overflow, the player gets assassinated instead. Advantages
+    of this: less code has to be changed, and the FP stuff is limited
+    so we don't need a good API for it, just a few functions that can
+    call the ROM directly, as needed: bank_deposit(), bank_withdraw(),
+    bank_interest(), bank_compare(). These will need a common ul_to_fp().
+    Also need a would_overflow(unsigned long value, unsigned long amount)
+    to return true if adding value + amount would overflow... actually it
+    can return MAX_LONG - value (still true, but also useful as a value).
+
   - Use a "bigint" library (e.g. 64-bit ints). Would still be
     possible to overflow, but it would take a really determined
     player. Disadvantage: slow. Maxes out at:
@@ -279,6 +298,16 @@ Other things that need doing to the code:
     million", this would be faster/easier than a regular bigint.
     Maxes out at 429,496,729,600,000 (429 trillion).
 
+  - Another hybrid idea, might be faster: one long ranging up to
+    999,999,999, or 1 billion - 1, and an unsigned int for the top
+    bits. Existing cprintfancy() can handle the bottom part, if the
+    top is 0. If not, we only ever need the top digit of the bottom
+    (e.g. the .2 in "1.2 billion"), and then only if the top int is
+    less than 10. Maxes out at 65.535 trillion, meaning we'll need
+    to be able to print "Trillion", perhaps with no space. This is
+    approximately equivalent to a 46-bit int, but uses 48 bits of
+    storage.
+
   - Leave it as-is. Obviously the easiest option, but not very satisfying.
     Maxes out at a measly 4.2 billion.
 
diff --git a/taipan.c b/taipan.c
index a30eb93..1ba5751 100644
--- a/taipan.c
+++ b/taipan.c
@@ -165,15 +165,23 @@ void backspace() {
 	if allow_all is true, allows '*', which is used for
 	'throw cargo' in sea_battle. */
 unsigned char get_item(unsigned char allow_all) {
-	unsigned char i;
+	// unsigned char i;
+
 	for(;;) {
+		/* using a switch makes the code 12 bytes smaller here
 		i = lcgetc();
-		switch(i) {
+		if(i == 'o') return 0;
+		if(i == 's') return 1;
+		if(i == 'a') return 2;
+		if(i == 'g') return 3;
+		if(allow_all && i == '*') return 4;
+		*/
+		switch(lcgetc()) {
 			case 'o': return 0;
 			case 's': return 1;
 			case 'a': return 2;
 			case 'g': return 3;
-			case '*': if(allow_all) return 4; /* else fall thru */
+			case '*': if(allow_all) return 4; // else fall thru
 			default: break;
 		}
 	}
@@ -292,9 +300,15 @@ void at_sea() {
 	revers(1);
 	cputs(location[0]);
 	revers(0);
+
+	/* this is 24 bytes smaller: */
+	cputs("   ");
+
+	/* than this:
 	cputc(' ');
 	cputc(' ');
 	cputc(' ');
+	*/
 }
 
 /* this bit of code was duplicated a *bunch* of times,
@@ -465,9 +479,12 @@ void cprintfancy_ctr(unsigned long num, unsigned char center) {
 		mil = 0;
 
 		if(center) {
+			cputs("   ");
+			/*
 			cputc(' ');
 			cputc(' ');
 			cputc(' ');
+			*/
 			tmp = 0;
 			for(tmp = 100L; tmp < 1000000L; tmp *= 100L)
 				if(num < tmp) cputc(' ');
@@ -521,17 +538,22 @@ void fancy_numbers(unsigned long num, char *fancy) {
 }
 */
 
+void justify_int(unsigned int num) {
+	if(num < 1000) cputc(' ');
+	if(num <  100) cputc(' ');
+	if(num <   10) cputc(' ');
+	cprintulong(num);
+}
+
 void hide_cursor() {
-	gotoxy(0,23); cputc(' ');
+	gotoxy(0,23);
+	cputc(' ');
 }
 
 void update_guns() {
 	revers(1);
 	gotoxy(31, 1);
-	if(guns < 1000) cputc(' ');
-	if(guns <  100) cputc(' ');
-	if(guns <   10) cputc(' ');
-	cprintulong(guns);
+	justify_int(guns);
 	revers(0);
 	hide_cursor();
 }
@@ -540,11 +562,7 @@ void fight_stats(int ships, int orders) {
 	cursor(0);
    gotoxy(0, 0);
 
-	if(ships < 1000) cputc(' ');
-	if(ships <  100) cputc(' ');
-	if(ships <   10) cputc(' ');
-	cprintulong(ships);
-
+	justify_int(ships);
 	cputs(" ship");
 	if(ships != 1) cputc('s');
 	cputs(" attacking, Taipan! \r\n");
@@ -651,6 +669,16 @@ int sea_battle(int id, int num_ships) {
 		cputs("\r\n");
       input = timed_getch(TMOUT_3S);
 
+		/* using a switch() instead of a chain of if/else
+			actually increases code size by 16 bytes!
+		switch(orders) {
+			case 'f': orders == 1;
+			case 'r': orders == 2;
+			case 't': orders == 3;
+			default: break;
+		}
+		*/
+
       if(input == 'f') {
          orders = 1;
       } else if(input == 'r') {
@@ -734,8 +762,7 @@ int sea_battle(int id, int num_ships) {
 				plus_or_space(num_ships > num_on_screen);
 
             gotoxy(0, 16);
-				cputc('\r');
-				cputc('\n');
+				cputs("\r\n");
 
             targeted = randi()%10;
             while(ships_on_screen[targeted] == 0) {
@@ -1116,7 +1143,7 @@ int sea_battle(int id, int num_ships) {
 long get_num(void) {
    static char number[20];
 	unsigned char count = 0;
-   int input;
+   char input;
 
 	cursor(1);
 	cblank(1);
@@ -1609,7 +1636,11 @@ void final_stats(void)
 	// __asm__("jmp $e477");
 
 	/* exit(0) works in DOS 2.0s and 2.5, known to fail in Sparta */
-	exit(0);
+	// exit(0);
+
+	/* let's try doing it this way. I suspect it will have the same
+		results as exit(0)... */
+	__asm__("jmp (10)"); // aka DOSVEC
 }
 
 void transfer(void)