Optimized float classification routines and changed return type to bool

Author: ZERICO2005

src/libc/include/__math_def.h

@@ -43,17 +43,17 @@ extern "C" {
 int _fpclassifyf(float n);
 int _fpclassifyl(long double n);
 
-int _isinff(float n);
-int _isnanf(float n);
-int _isnormalf(float n);
-int _isfinitef(float n);
-int _iszerof(float n);
-int _issubnormalf(float n);
+bool _isinff(float n);
+bool _isnanf(float n);
+bool _isnormalf(float n);
+bool _isfinitef(float n);
+bool _iszerof(float n);
+bool _issubnormalf(float n);
 
 int _isinfl(long double n);
 int _isnanl(long double n);
-int _isnormall(long double n);
-int _isfinitel(long double n);
+bool _isnormall(long double n);
+bool _isfinitel(long double n);
 int _iszerol(long double n);
 int _issubnormall(long double n);
 

src/libc/isfinitef.src

@@ -1,19 +1,17 @@
 	assume	adl=1
 
 	section	.text
+
 	public	__isfinitef
+
+; bool _isfinitef(float)
 __isfinitef:
-	pop	bc
-	pop	hl
-	pop	de
-	push	de
-	push	hl
-	push	bc
-	add	hl,hl
-	ld	a,e
-	rla
-	add	a,1
-	sbc	hl,hl
-	inc	hl
+	ld	hl, 5
+	add	hl, sp
+	ld	hl, (hl)
+	add	hl, hl
+	ld	a, h
+	sub	a, $FF	; NaN/inf exponent won't underflow
+	sbc	a, a
 	ret
 

src/libc/isfinitel.src

@@ -4,14 +4,14 @@
 
 	public	__isfinitel
 
-; int _isfinitel(long double)
+; bool _isfinitel(long double)
 __isfinitel:
 	ld	hl, 8
 	add	hl, sp
 	ld	hl, (hl)	; load the upper 24bits
 	add	hl, hl	; clears signbit
 	ld	de, $2000	; (1 << (5 + 8))
 	add	hl, de	; attempts to overflow the exponent
-	sbc	hl, hl
-	inc	hl
+	sbc	a, a
+	inc	a
 	ret

src/libc/isinff.src

@@ -1,19 +1,20 @@
 	assume	adl=1
 
 	section	.text
+
 	public	__isinff
+
+; bool _isinff(float)
 __isinff:
-	ld	iy,0
-	add	iy,sp
-	ld	hl,(iy+3)
-	adc	hl,hl
-	jr	nz,.finite
-	ld	a,(iy+6)
+	xor	a, a
+	ld	iy, 0
+	add	iy, sp
+	ld	hl, (iy+3)
+	adc	hl, hl
+	ret	nz	; finite or NaN
+	; HL is zero
+	ld	a, (iy+6)
 	rla
-	inc	a
-	inc	hl
-	ret	z
-.finite:
-	or	a,a
-	sbc	hl,hl
+	add	a, 1	; attempt to overflow the exponent
+	sbc	a, a
 	ret

src/libc/isnanf.src

@@ -1,20 +1,19 @@
 	assume	adl=1
 
 	section	.text
-	
+
 	public	__isnanf
-	
+
+; bool _isnanf(float)
 __isnanf:
-	ld	iy,0
-	add	iy,sp
-	ld	hl,(iy+3)
-	adc	hl,hl
-	jr	z,.l
-	ld	hl,(iy+5)
-	add	hl,hl
-.l:
-	inc	h
-	ld	hl,0
-	ret	nz
-	inc	hl
+	xor	a, a
+	ld	iy, 0
+	add	iy, sp
+	ld	hl, (iy+3)
+	adc	hl, hl
+	ret	z	; infinity
+	ld	a, (iy+6)
+	rla
+	add	a, 1	; attempt to overflow the exponent
+	sbc	a, a
 	ret

src/libc/isnormalf.src

@@ -4,7 +4,7 @@
 
 	public	__isnormalf
 
-; int _isnormalf(float)
+; bool _isnormalf(float)
 __isnormalf:
 	ld	hl, 5
 	add	hl, sp
@@ -13,6 +13,5 @@ __isnormalf:
 	ld	a, h
 	dec	a
 	cp	a, $FE	; tests for zero/denormal/inf/NaN exponents
-	sbc	hl, hl	; -1 if normal, 0 otherwise
+	sbc	a, a	; -1 if normal, 0 otherwise
 	ret
-

src/libc/isnormall.src

@@ -4,7 +4,7 @@
 
 	public	__isnormall
 
-; int _isnormall(long double)
+; bool _isnormall(long double)
 __isnormall:
 	; load upper 24bits
 	ld	hl, 8	
@@ -24,6 +24,6 @@ __isnormall:
 
 .exp_all_ones:
 .exp_all_zero:
-	sbc	hl, hl
-	inc	hl
+	sbc	a, a
+	inc	a
 	ret

src/libc/issubnormalf.src

@@ -4,16 +4,16 @@
 
 	public	__issubnormalf
 
-; int _issubnormalf(float)
+; bool _issubnormalf(float)
 __issubnormalf:
-	pop	bc, hl, de
-	push	de, hl, bc
-	or	a, a
+	xor	a, a
+	pop	bc, hl
 	adc	hl, hl
-	ret z	; zero mantissa is not subnormal
-	ld	a, e
-	adc	a, a
-	ret z	; zero exponent is subnormal
-	or	a, a
-	sbc	hl, hl
+	ex	(sp), hl
+	push	hl, bc
+	ret	z	; zero mantissa is not subnormal
+	adc	hl, hl
+	sub	a, l
+	sbc	a, a
+	inc	a
 	ret

src/libc/iszerof.src

@@ -1,21 +1,19 @@
 	assume	adl=1
 
 	section	.text
-	
+
 	public	__iszerof
 
-; int iszerof(float)
+; bool _iszerof(float)
 __iszerof:
-	pop	bc, hl, de
-	push	de, hl, bc
-	or	a, a
+	xor	a, a
+	pop	bc, hl
 	adc	hl, hl
-	jr	nz, .not_zero_f32
-	rl	e
-	jr	nz, .not_zero_f32
-	inc	hl
-	ret
-.not_zero_f32:
-	or	a, a
-	sbc	hl, hl
+	ex	(sp), hl
+	push	hl, bc
+	ret	nz	; non-zero mantissa
+	ld	a, l
+	adc	a, a
+	sub a, 1
+	sbc	a, a
 	ret

test/floating_point/float32_classification/src/main.c

@@ -136,7 +136,7 @@ int main(void) {
         printf("All tests passed");
     } else {
         printf(
-            "Failed test:\n0x%08lX\nTruth: %X_%d\nGuess: %X_%d",
+            "Failed test:\n0x%08lX\nTruth: %06X_%d\nGuess: %06X_%d",
             ret.failed_index, ret.guess, ret.guess_fp, ret.truth, ret.truth_fp
         );
     }