implemented another batch of small floating point routiines

c64/basic/,stubs_math/bf7b.pwr_FAC2_FAC1.s

@@ -21,5 +21,5 @@
 
 // XXX provide implementation
 
-FPWRT:
+pwr_FAC2_FAC1:
 	STUB_IMPLEMENTATION()

c64/basic/math/b849.add_HALF_FAC1.s

@@ -9,8 +9,9 @@
 // See also:
 // - [CM64] Computes Mapping the Commodore 64 - page 112
 
-// XXX implement
-
 add_HALF_FAC1:
 
-	STUB_IMPLEMENTATION()
+	ldy #>const_HALF
+	lda #<const_HALF
+
+	jmp add_MEM_FAC1

c64/basic/math/bafe.div10_FAC1_p.s

@@ -16,7 +16,14 @@
 // - https://codebase64.org/doku.php?id=base:kernal_floating_point_mathematics
 //
 
-// XXX provide implementation
+// XXX test this
 
 div10_FAC1_p:
-	STUB_IMPLEMENTATION()
+
+	lda #$00
+	sta FAC1_sign
+
+	ldy #>const_TEN
+	lda #<const_TEN
+
+	jmp div_MEM_FAC1

c64/basic/math/bc2b.sgn_FAC1_A.s

@@ -15,7 +15,12 @@
 // - https://codebase64.org/doku.php?id=base:kernal_floating_point_mathematics
 //
 
-// XXX provide implementation
-
 sgn_FAC1_A:
-	STUB_IMPLEMENTATION()
+
+	lda FAC1_exponent
+	beq !+
+	lda FAC1_sign
+	bne !+
+	lda #$01
+!:
+	rts

c64/basic/math/bf71.sqr_FAC1.s

@@ -15,7 +15,8 @@
 // - https://codebase64.org/doku.php?id=base:kernal_floating_point_mathematics
 //
 
-// XXX provide implementation
-
 sqr_FAC1:
-	STUB_IMPLEMENTATION()
+
+	jsr mov_FAC1_FAC2
+	
+	// FALLLTROUGH to sqr_FAC2

c64/basic/math/bf78.pwr_FAC2_MEM.s

@@ -4,7 +4,7 @@
 // #LAYOUT# *   *       #IGNORE
 
 //
-// Math package - set FAC1 as RAM raised to the power of FAC1
+// Math package - set FAC1 as RAM raised to the power of FAC2
 //
 // Input:
 // - .A - address low byte
@@ -12,11 +12,13 @@
 //
 // See also:
 // - [CM64] Computes Mapping the Commodore 64 - page 117 (FPWRT)
+// - https://www.c64-wiki.com/wiki/BASIC-ROM
 // - https://www.c64-wiki.com/wiki/Floating_point_arithmetic
 // - https://codebase64.org/doku.php?id=base:kernal_floating_point_mathematics
 //
 
-// XXX provide implementation
+pwr_FAC2_MEM:
 
-FPWR:
-	STUB_IMPLEMENTATION()
+	jsr mov_MEM_FAC1
+
+	// FALLTROUGH to pwr_FAC2_FAC1