Add pseudoteletypewriter to emulator

https://justine.storage.googleapis.com/emulator628.mp4

libc/tinymath/fpclassify.S

@@ -21,7 +21,7 @@
 #include "libc/macros.h"
 .source	__FILE__
 
-__fpclassify:
+tinymath_fpclassify:
 	.leafprologue
 	movd	%xmm0,%rax
 	movd	%xmm0,%rdx
@@ -41,4 +41,5 @@ __fpclassify:
 	sal	$12,%rdx
 	sete	%al
 1:	.leafepilogue
-	.endfn	__fpclassify,globl
+	.endfn	tinymath_fpclassify,globl
+	.alias	tinymath_fpclassify,__fpclassify

libc/tinymath/fpclassifyf.S

@@ -21,7 +21,7 @@
 #include "libc/macros.h"
 .source	__FILE__
 
-__fpclassifyf:
+tinymath_fpclassifyf:
 	.leafprologue
 	movd	%xmm0,%edx
 	movd	%xmm0,%eax
@@ -42,4 +42,5 @@ __fpclassifyf:
 	sete	%al
 	movzbl	%al,%eax
 1:	.leafepilogue
-	.endfn	__fpclassifyf,globl
+	.endfn	tinymath_fpclassifyf,globl
+	.alias	tinymath_fpclassifyf,__fpclassifyf

libc/tinymath/fpclassifyl.S

@@ -21,7 +21,7 @@
 #include "libc/macros.h"
 .source	__FILE__
 
-__fpclassifyl:
+tinymath_fpclassifyl:
 	push	%rbp
 	mov	%rsp,%rbp
 	mov	24(%rbp),%rax
@@ -50,4 +50,5 @@ __fpclassifyl:
 	and	$FP_NORMAL,%eax
 1:	pop	%rbp
 	ret
-	.endfn	__fpclassifyl,globl
+	.endfn	tinymath_fpclassifyl,globl
+	.alias	tinymath_fpclassifyl,__fpclassifyl

libc/tinymath/scalbn.S

@@ -20,6 +20,10 @@
 #include "libc/macros.h"
 .source	__FILE__
 
+/	Returns 𝑥 × 2ʸ.
+/
+/	@param	𝑥 is double passed in %xmm0
+/	@param	𝑦 is exponent via %edi
 tinymath_scalbn:
 	push	%rbp
 	mov	%rsp,%rbp

libc/tinymath/scalbnf.S

@@ -20,6 +20,10 @@
 #include "libc/macros.h"
 .source	__FILE__
 
+/	Returns 𝑥 × 2ʸ.
+/
+/	@param	𝑥 is float passed in %xmm0
+/	@param	𝑦 is exponent via %edi
 tinymath_scalbnf:
 	push	%rbp
 	mov	%rsp,%rbp

libc/tinymath/scalbnl.S

@@ -20,11 +20,10 @@
 #include "libc/macros.h"
 .source	__FILE__
 
-/	Returns 𝑥 × 𝑟ʸ where 𝑟 is radix of hardware architecture.
+/	Returns 𝑥 × 2ʸ.
 /
 /	@param	𝑥 is long double passed on stack
 /	@param	𝑦 is exponent via %edi
-/	@see	FLT_RADIX
 tinymath_scalbnl:
 	push	%rbp
 	mov	%rsp,%rbp