Add 24-bit integer-to-float routine and floating-point jiffy clock reader (#150)

* feat: add routine to convert 24-bit integer from A/X/Y to float in FAC1

* fix: remove duplicate definition

* fix: shift to appropriate exponent

compiler/res/prog8lib/c64/floats.p8

@@ -36,7 +36,7 @@ romsub $b1bf = AYINT() clobbers(A,X,Y)          ; fac1-> signed word in 100-101
 ; there is also floats.GIVUAYFAY - unsigned word in A/Y (lo/hi) to fac1
 ; there is also floats.FREADS32  that reads from 98-101 ($62-$65) MSB FIRST
 ; there is also floats.FREADUS32  that reads from 98-101 ($62-$65) MSB FIRST
-; there is also floats.FREADS24AXY  that reads signed int24 into fac1 from A/X/Y (lo/mid/hi bytes)
+; there is also floats.FREAD{S,U}24AXY  that read (un)signed int24 into fac1 from A/X/Y (lo/mid/hi bytes)
 romsub $b391 = GIVAYF(ubyte lo @ Y, ubyte hi @ A) clobbers(A,X,Y)
 
 romsub $b3a2 = FREADUY(ubyte value @ Y) clobbers(A,X,Y)     ; 8 bit unsigned Y -> float in fac1
@@ -104,7 +104,6 @@ asmsub  FREADUS32  () clobbers(A,X,Y)  {
 
 asmsub  FREADS24AXY  (ubyte lo @ A, ubyte mid @ X, ubyte hi @ Y) clobbers(A,X,Y)  {
 	; ---- fac1 = signed int24 (A/X/Y contain lo/mid/hi bytes)
-	;      note: there is no FREADU24AXY (unsigned), use FREADUS32 instead.
 	%asm {{
 		sty  $62
 		stx  $63
@@ -119,6 +118,38 @@ asmsub  FREADS24AXY  (ubyte lo @ A, ubyte mid @ X, ubyte hi @ Y) clobbers(A,X,Y)
 	}}
 }
 
+asmsub FREADU24AXY(ubyte lo @ A, ubyte mid @ X, ubyte hi @ Y) clobbers(A, X, Y) -> float @FAC1 {
+        %asm{{
+                 FAC = $61
+                 sty FAC+1
+                 stx FAC+2
+                 sta FAC+3
+
+                 cpy #$00
+                 bne +
+                 cpx #$00
+                 bne +
+                 cmp #$00
+                 beq ++
+
+              +  ldx #$98
+                 bit FAC+1
+                 bmi +
+
+              -  dex
+                 asl FAC+3
+                 rol FAC+2
+                 rol FAC+1
+                 bpl -
+
+              +  stx FAC
+                 lda #$00
+                 sta FAC+4
+                 sta FAC+5
+                 rts
+       }}
+}
+
 asmsub  GIVUAYFAY  (uword value @ AY) clobbers(A,X,Y)  {
 	; ---- unsigned 16 bit word in A/Y (lo/hi) to fac1
 	%asm {{
@@ -177,6 +208,13 @@ asmsub normalize(float value @FAC1) -> float @ FAC1 {
     }}
 }
 
+; get the jiffy clock as a float
+asmsub time() -> float @ FAC1 {
+    %asm {{
+        jsr cbm.RDTIM
+        jmp floats.FREADU24AXY
+    }}
+}
 
 %asminclude "library:c64/floats.asm"
 %asminclude "library:c64/floats_funcs.asm"

compiler/res/prog8lib/cx16/floats.p8

@@ -90,6 +90,37 @@ asmsub  FREADSA  (byte value @A) clobbers(A,X,Y) {
     }}
 }
 
+asmsub FREADU24AXY(ubyte lo @ A, ubyte mid @ X, ubyte hi @ Y) clobbers(A, X, Y) -> float @FAC1 {
+        %asm{{
+                 FAC = $C3
+                 sty FAC+1
+                 stx FAC+2
+                 sta FAC+3
+
+                 cpy #$00
+                 bne +
+                 cpx #$00
+                 bne +
+                 cmp #$00
+                 beq ++
+
+              +  ldx #$98
+                 bit FAC+1
+                 bmi +
+
+              -  dex
+                 asl FAC+3
+                 rol FAC+2
+                 rol FAC+1
+                 bpl -
+
+               + stx FAC
+                 stz FAC+4
+                 stz FAC+5
+                 rts
+       }}
+}
+
 asmsub  GIVUAYFAY  (uword value @ AY) clobbers(A,X,Y)  {
 	; ---- unsigned 16 bit word in A/Y (lo/hi) to fac1
 	%asm {{
@@ -157,7 +188,6 @@ _msg    .text 13,"?rom 47+ required for val1",13,0
     }}
 }
 
-
 &uword AYINT_facmo = $c6      ; $c6/$c7 contain result of AYINT   (See "basic.sym" kernal symbol file)
 
 sub rnd() -> float {
@@ -173,6 +203,14 @@ asmsub normalize(float value @FAC1) -> float @ FAC1 {
     }}
 }
 
+; get the jiffy clock as a float
+asmsub time() -> float @ FAC1 {
+    %asm {{
+        jsr cbm.RDTIM
+        jmp floats.FREADU24AXY
+    }}
+}
+
 %asminclude "library:c64/floats.asm"
 %asminclude "library:c64/floats_funcs.asm"