small utils.h comment fixes

1 files changed, 12 insertions, 12 deletions

diff --git a/utils.h b/utils.h
index e1258c9..7d9a15b 100644
--- a/utils.h
+++ b/utils.h
@@ -54,7 +54,7 @@ static inline uint32_t linear_addr(const void __far * ptr)
 
 /** 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);
+static uint16_t scaleu(uint16_t x, uint16_t srcmax, uint16_t dstmax);
 #pragma aux scaleu = \
 	"mul cx" /* dx:ax = x * dstmax */\
 	"div bx" /* ax = dx:ax / srcmax */\
@@ -62,19 +62,19 @@ static unsigned scaleu(unsigned x, unsigned srcmax, unsigned dstmax);
 	__value [ax] \
 	__modify exact [ax dx]
 
-/** Map x linearly from range [0, srcmax] to [0, 2^dstmax].
+/** Map x linearly from range [0, 2^srcmax_bits] to [0, dstmax].
  *  Equivalent to above, but uses shift instead of division. */
-static unsigned scaleu_shift(unsigned x, unsigned char srcmax, unsigned dstmax);
+static uint16_t scaleu_shift(uint16_t x, uint8_t srcmax_bits, uint16_t dstmax);
 #pragma aux scaleu_shift = \
 	"mul dx" /* dx:ax = x * dstmax */ \
-	"shrd ax, dx, cl" /* ax = dx:ax / 2^srcmax */ \
+	"shrd ax, dx, cl" /* ax = dx:ax / 2^srcmax_bits */ \
 	__parm [ax] [cl] [dx] \
 	__value [ax] \
 	__modify exact [ax dx]
 
-/** Map x linearly from range [0, srcmax] to [0, dstmax].
+/** Map x linearly from range [-srcmax, srcmax] to [-dstmax, dstmax].
  *  Equivalent of (x * dstmax) / srcmax but with 32-bit signed precision. */
-static int scalei(int x, int srcmax, int dstmax);
+static int16_t scalei(int16_t x, int16_t srcmax, int16_t dstmax);
 #pragma aux scalei = \
 	"imul cx" /* dx:ax = x * dstmax */ \
 	"idiv bx" /* ax = dx:ax / srcmax */ \
@@ -82,24 +82,24 @@ static int scalei(int x, int srcmax, int dstmax);
 	__value [ax] \
 	__modify exact [ax dx]
 
-/** Map x linearly from range [0, srcmax] to [0, dstmax].
+/** Map x linearly from range [-srcmax, srcmax] to [-dstmax, dstmax].
  *  Equivalent to scalei, but the division remainder is returned in rem,
  *  which can be reused in future calls to reduce rounding error. */
-static int scalei_rem(int x, int srcmax, int dstmax, short *rem);
+static int16_t scalei_rem(int16_t x, int16_t srcmax, int16_t dstmax, int16_t *rem);
 #pragma aux scalei_rem = \
 	"imul cx"       /* dx:ax = x * dstmax */ \
 	"mov cx, [si]"  /* cx = rem */ \
 	"test cx, cx" \
-	"setns cl"      /* cl = 1 if rem positive, 0 if negative */ \
+	"setns cl"      /* cl = 1 if rem sign positive, 0 if negative */ \
 	"movzx cx, cl" \
-	"dec cx"        /* cx = 0 if rem positive, -1 if negative */ \
+	"dec cx"        /* cx = 0 if rem positive, -1 if negative => rem sign extended */ \
 	"add ax, [si]"  /* ax += *rem */ \
-	"adc dx, cx"    /* dx += 1 if carry and rem positive, 0 if carry and rem negative (aka. signed addition) */ \
+	"adc dx, cx"    /* dx += "upper part of rem" +cf */ \
 	"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 si]
+	__modify [ax cx dx]
 
 /** Sign extend x from b bits to 16. */
 static inline int16_t sign_extend(int16_t x, int b)