initial import of DOS mouse driver

1 files changed, 94 insertions, 0 deletions

diff --git a/utils.h b/utils.h
new file mode 100644
index 0000000..4740644
--- /dev/null
+++ b/utils.h
@@ -0,0 +1,94 @@
+#ifndef UTILS_H
+#define UTILS_H
+
+#include <stdint.h>
+
+#define ABS(x) (((x) < 0) ? -(x) : (x))
+
+#define MIN(a,b)  (((a) < (b)) ? (a) : (b))
+#define MAX(a,b)  (((a) > (b)) ? (a) : (b))
+
+#define BOUND(x,a,b) ( MIN(b, MAX(a, x)) )
+
+static inline void breakpoint(void);
+#pragma aux breakpoint = 0xcd 0x03;
+
+static inline void cli(void);
+#pragma aux cli = "cli"
+
+static inline void sti(void);
+#pragma aux sti = "sti"
+
+/** Map x linearly from range [0, srcmax] to [0, dstmax].
+ *  Equivalent of (x * dstmax) / srcmax but with 32-bit unsigned precision. */
+static unsigned scaleu(unsigned x, unsigned srcmax, unsigned dstmax);
+#pragma aux scaleu = \
+	"mul cx" /* dx:ax = x * dstmax */\
+	"div bx" /* ax = dx:ax / srcmax */\
+	__parm [ax] [bx] [cx] \
+	__value [ax] \
+	__modify [ax cx dx]
+
+/** Map x linearly from range [0, srcmax] to [0, dstmax].
+ *  Equivalent of (x * dstmax) / srcmax but with 32-bit signed precision.
+ *  Division remainder is returned in rem, which should be reused
+ *  in future calls to reduce rounding error. */
+static int scalei_rem(int x, int srcmax, int dstmax, short *rem);
+#pragma aux scalei_rem = \
+	"imul cx"       /* dx:ax = x * dstmax */ \
+	"add ax, [si]"  /* ax += *rem */ \
+	"adc dx, 0"     /* dx += 1 if carry */ \
+	"idiv bx"       /* ax = dx:ax / srcmax, dx = new remainder */ \
+	"mov [si], dx"  /* store the new remainder */ \
+	__parm [ax] [bx] [cx] [si] \
+	__value [ax] \
+	__modify [ax cx dx]
+
+static void bzero(void __far *buf, unsigned int size);
+#pragma aux bzero = \
+	"cld" \
+	"mov ax, 0" \
+	"rep stos byte ptr es:[di]" \
+	__parm [es di] [cx] \
+	__modify [ax]
+
+static void nfmemcpy(void __far *dst, const void *src, unsigned int size);
+#pragma aux nfmemcpy = \
+	"cld" \
+	"rep movs byte ptr es:[di], byte ptr ds:[si]" \
+	__parm [es di] [si] [cx] \
+	__modify [cx si di]
+
+static void fnmemcpy(void *dst, const void __far *src, unsigned int size);
+#pragma aux fnmemcpy = \
+	"cld" \
+	"push gs" \
+	"mov ax, es" \
+	"mov gs, ax" /* gs is now the src segment */ \
+	"mov ax, ds" \
+	"mov es, ax" /* es is now ds, the dst segment */ \
+	"rep movs byte ptr es:[di], byte ptr gs:[si]" \
+	"pop gs" \
+	__parm [di] [es si] [cx] \
+	__modify [ax cx si di es]
+
+static void ffmemcpy(void __far *dst, const void __far *src, unsigned int size);
+#pragma aux ffmemcpy = \
+	"cld" \
+	"push gs" \
+	"mov gs, ax" \
+	"rep movs byte ptr es:[di], byte ptr gs:[si]" \
+	"pop gs" \
+	__parm [es di] [gs si] [cx] \
+	__modify [cx si di]
+
+static void nnmemcpy(void *dst, const void *src, unsigned int size);
+#pragma aux nnmemcpy = \
+	"cld" \
+	"mov ax, ds" \
+	"mov es, ax" /* es is now ds, the src+dst segment */ \
+	"rep movs byte ptr es:[di], byte ptr ds:[si]" \
+	__parm [di] [si] [cx] \
+	__modify [cx si di es]
+
+#endif