Added hardware random option and added function to set seed

Makefile

@@ -13,7 +13,7 @@ ASFLAGS = -plosgff
 SRC = \
 src/crt0.s \
 src/bios.s \
-src/random.s \
+src/random.c \
 src/console.c \
 
 OBJ_1 = $(notdir $(SRC:.c=.rel))

include/random.h

@@ -1,3 +1,11 @@
 #include "types.h"
 
+// Get a pseudo random number
 uint8_t random();
+// Set the seed for the random number generator
+void random_set_seed(uint8_t seed);
+
+// Get a random number from hardware
+uint8_t random_hw();
+
+

src/random.c

@@ -0,0 +1,48 @@
+#include "random.h"
+
+uint8_t random_seed;
+
+// Fast RND
+//
+// An 8-bit pseudo-random number generator,
+// using a similar method to the Spectrum ROM,
+// - without the overhead of the Spectrum ROM.
+//
+// R = random number seed
+// an integer in the range [1, 256]
+//
+// R -> (33*R) mod 257
+//
+// S = R - 1
+// an 8-bit unsigned integer
+
+uint8_t random()  __naked {
+	__asm
+		ld a, (_random_seed)
+		ld b, a 
+
+		rrca ; multiply by 32
+		rrca
+		rrca
+		xor #0x1f
+
+		add a, b
+		sbc a, #255 ; carry
+
+		ld (_random_seed), a
+		ld l, a
+		ret
+	__endasm;
+}
+
+void random_set_seed(uint8_t seed) {
+	random_seed = seed;
+}
+
+uint8_t random_hw() __naked {
+	__asm
+		in a, (0x09)
+		ld l, a
+		ret
+	__endasm;
+}

src/random.s

@@ -1,31 +0,0 @@
-; Fast RND
-;
-; An 8-bit pseudo-random number generator,
-; using a similar method to the Spectrum ROM,
-; - without the overhead of the Spectrum ROM.
-;
-; R = random number seed
-; an integer in the range [1, 256]
-;
-; R -> (33*R) mod 257
-;
-; S = R - 1
-; an 8-bit unsigned integer
-
-	.area _CODE
-
-_random::
-	ld a, (_random_seed)
-	ld b, a 
-
-	rrca ; multiply by 32
-	rrca
-	rrca
-	xor #0x1f
-
-	add a, b
-	sbc a, #255 ; carry
-
-	ld (_random_seed), a
-	ld l, a
-	ret