aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--NOTES.txt4
-rw-r--r--rand.s12
-rw-r--r--taipan.c6
3 files changed, 19 insertions, 3 deletions
diff --git a/NOTES.txt b/NOTES.txt
index 6d8d37f..6825336 100644
--- a/NOTES.txt
+++ b/NOTES.txt
@@ -23,6 +23,10 @@ arcade game).
Deliberate differences between the Apple II and Atari ports:
+0. The Atari version is noticeably faster than the Apple version on II+ or
+ IIe. This is because it's written in C and assembly, not interpreted
+ BASIC. A IIgs on the other hand...
+
1. "Press ESC for help" rather than ESC to start. Starting the game is
done with the space bar or return key.
diff --git a/rand.s b/rand.s
index a284592..6efcabd 100644
--- a/rand.s
+++ b/rand.s
@@ -1,5 +1,5 @@
- .export _randl
+ .export _randl, _rand1to3
.import _rand
; .export _randb, _randi, _randl
; .export _rand1in5
@@ -27,6 +27,16 @@ _randl:
ldx tmp3
rts
+; return 1, 2, or 3. equivalent to: randi()%3+1
+; replacing both occurences of the expression in taipan.c with a calls
+; to this function saves 11 bytes.
+_rand1to3:
+ jsr _rand ; returns 16 bits: X is MSB (which we ignore), A is LSB
+ and #$03 ; A now 0..3
+ beq _rand1to3 ; try again, if it's 0
+ ldx #0 ; now A is 1..3, but we have to force X to 0...
+ rts
+
;;; rest of file is commented out
; RANDOM is the POKEY LFSR read address. According to the POKEY data
diff --git a/taipan.c b/taipan.c
index bd67589..d1cb8ed 100644
--- a/taipan.c
+++ b/taipan.c
@@ -97,6 +97,8 @@ extern unsigned int __fastcall__ randi(void);
#define randi() ((unsigned int)rand())
#endif
+extern unsigned char rand1to3(void);
+
/* random long, 0 to 2**32-1 */
extern unsigned long __fastcall__ randl(void);
@@ -1626,7 +1628,7 @@ void cash_or_guns(void) {
void set_prices(void) {
char i;
for(i = 0; i < 4; ++i)
- price[i] = base_price[i][port] / 2 * (randi()%3 + 1) * base_price[i][0];
+ price[i] = base_price[i][port] / 2 * rand1to3() * base_price[i][0];
}
unsigned int warehouse_in_use() {
@@ -2825,7 +2827,7 @@ void elder_brother_wu(void) {
}
if((debt > 20000) && (cash > 0) && (one_chance_in(5))) {
- unsigned char num = randi()%3 + 1;
+ unsigned char num = rand1to3();
cash = 0;
port_stats();