Make comments more consistent

- Changes most `/* comments */` to `// comments`
- Changes `/**` block comments consistently to `/*`
- Adds consistent license comments to all files

Also renames `T_POP_SET` to `T_Z80_SET`

src/asm/fixpoint.c

@@ -6,9 +6,7 @@
  * SPDX-License-Identifier: MIT
  */
 
-/*
- * Fixed-point math routines
- */
+// Fixed-point math routines
 
 #include <inttypes.h>
 #include <math.h>
@@ -30,9 +28,6 @@
 #define M_PI 3.14159265358979323846
 #endif
 
-/*
- * Print a fixed point value
- */
 void fix_Print(int32_t i)
 {
 	uint32_t u = i;
@@ -47,121 +42,76 @@ void fix_Print(int32_t i)
 	       ((uint32_t)(fix2double(u) * 100000 + 0.5)) % 100000);
 }
 
-/*
- * Calculate sine
- */
 int32_t fix_Sin(int32_t i)
 {
 	return double2fix(sin(fdeg2rad(fix2double(i))));
 }
 
-/*
- * Calculate cosine
- */
 int32_t fix_Cos(int32_t i)
 {
 	return double2fix(cos(fdeg2rad(fix2double(i))));
 }
 
-/*
- * Calculate tangent
- */
 int32_t fix_Tan(int32_t i)
 {
 	return double2fix(tan(fdeg2rad(fix2double(i))));
 }
 
-/*
- * Calculate arcsine
- */
 int32_t fix_ASin(int32_t i)
 {
 	return double2fix(rad2fdeg(asin(fix2double(i))));
 }
 
-/*
- * Calculate arccosine
- */
 int32_t fix_ACos(int32_t i)
 {
 	return double2fix(rad2fdeg(acos(fix2double(i))));
 }
 
-/*
- * Calculate arctangent
- */
 int32_t fix_ATan(int32_t i)
 {
 	return double2fix(rad2fdeg(atan(fix2double(i))));
 }
 
-/*
- * Calculate atan2
- */
 int32_t fix_ATan2(int32_t i, int32_t j)
 {
 	return double2fix(rad2fdeg(atan2(fix2double(i), fix2double(j))));
 }
 
-/*
- * Multiplication
- */
 int32_t fix_Mul(int32_t i, int32_t j)
 {
 	return double2fix(fix2double(i) * fix2double(j));
 }
 
-/*
- * Division
- */
 int32_t fix_Div(int32_t i, int32_t j)
 {
 	return double2fix(fix2double(i) / fix2double(j));
 }
 
-/*
- * Modulo
- */
 int32_t fix_Mod(int32_t i, int32_t j)
 {
 	return double2fix(fmod(fix2double(i), fix2double(j)));
 }
 
-/*
- * Power
- */
 int32_t fix_Pow(int32_t i, int32_t j)
 {
 	return double2fix(pow(fix2double(i), fix2double(j)));
 }
 
-/*
- * Logarithm
- */
 int32_t fix_Log(int32_t i, int32_t j)
 {
 	return double2fix(log(fix2double(i)) / log(fix2double(j)));
 }
 
-/*
- * Round
- */
 int32_t fix_Round(int32_t i)
 {
 	return double2fix(round(fix2double(i)));
 }
 
-/*
- * Ceil
- */
 int32_t fix_Ceil(int32_t i)
 {
 	return double2fix(ceil(fix2double(i)));
 }
 
-/*
- * Floor
- */
 int32_t fix_Floor(int32_t i)
 {
 	return double2fix(floor(fix2double(i)));