Make fixes and improvements

- Fix handling of precision in hex float formatting
- Enhance the cocmd interpreter for system() and popen()
- Manually ran the Lua unit tests, which are now passing
- Let stdio i/o operations happen when file is in error state
- We're now saving and restoring xmm in ftrace out of paranoia

libc/nexgen32e/nt2sysv.S

@@ -36,20 +36,18 @@ __nt2sysv:
 	mov	%rsp,%rbp
 //	TODO(jart): We should probably find some way to use our own
 //	            stack when Windows delivers signals ;_;
-	sub	$0x100,%rsp
+	sub	$256,%rsp
 	push	%rbx
 	push	%rdi
 	push	%rsi
-	pushf					# TODO(jart): Do we need it?
-	lea	-0x80(%rbp),%rdi
-	call	_savexmm
+	pushf					// TODO(jart): Do we need it?
+	call	__xmm_save
 	mov	%rcx,%rdi
 	mov	%rdx,%rsi
 	mov	%r8,%rdx
 	mov	%r9,%rcx
 	call	*%rax
-	lea	-0x80(%rbp),%rdi
-	call	_loadxmm
+	call	__xmm_load
 	popf
 	pop	%rsi
 	pop	%rdi

libc/nexgen32e/savexmm.S

@@ -1,44 +0,0 @@
-/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8     -*-│
-│vi: set et ft=asm ts=8 tw=8 fenc=utf-8                                     :vi│
-╞══════════════════════════════════════════════════════════════════════════════╡
-│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
-│                                                                              │
-│ Permission to use, copy, modify, and/or distribute this software for         │
-│ any purpose with or without fee is hereby granted, provided that the         │
-│ above copyright notice and this permission notice appear in all copies.      │
-│                                                                              │
-│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
-│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
-│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
-│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
-│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
-│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
-│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
-│ PERFORMANCE OF THIS SOFTWARE.                                                │
-╚─────────────────────────────────────────────────────────────────────────────*/
-#include "libc/macros.internal.h"
-
-//	Stores XMM registers to buffer.
-//
-//	@param	%rdi points to &(forcealign(16) uint8_t[256])[128]
-//	@note	modern cpus have out-of-order execution engines
-_savexmm:
-	.leafprologue
-	movaps	%xmm0,-0x80(%rdi)
-	movaps	%xmm1,-0x70(%rdi)
-	movaps	%xmm2,-0x60(%rdi)
-	movaps	%xmm3,-0x50(%rdi)
-	movaps	%xmm4,-0x40(%rdi)
-	movaps	%xmm5,-0x30(%rdi)
-	movaps	%xmm6,-0x20(%rdi)
-	movaps	%xmm7,-0x10(%rdi)
-	movaps	%xmm8,0x00(%rdi)
-	movaps	%xmm9,0x10(%rdi)
-	movaps	%xmm10,0x20(%rdi)
-	movaps	%xmm11,0x30(%rdi)
-	movaps	%xmm12,0x40(%rdi)
-	movaps	%xmm13,0x50(%rdi)
-	movaps	%xmm14,0x60(%rdi)
-	movaps	%xmm15,0x70(%rdi)
-	.leafepilogue
-	.endfn	_savexmm,globl,hidden

libc/nexgen32e/xmm.S

@@ -17,28 +17,48 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/macros.internal.h"
+.privileged
 
-//	Loads XMM registers from buffer.
-//
-//	@param	%rdi points to &(forcealign(16) uint8_t[256])[128]
-//	@note	modern cpus have out-of-order execution engines
-_loadxmm:
+__xmm_save:
+	lea	-128(%rbp),%rdi
 	.leafprologue
-	movaps	-0x80(%rdi),%xmm0
-	movaps	-0x70(%rdi),%xmm1
-	movaps	-0x60(%rdi),%xmm2
-	movaps	-0x50(%rdi),%xmm3
-	movaps	-0x40(%rdi),%xmm4
-	movaps	-0x30(%rdi),%xmm5
-	movaps	-0x20(%rdi),%xmm6
-	movaps	-0x10(%rdi),%xmm7
-	movaps	0x00(%rdi),%xmm8
-	movaps	0x10(%rdi),%xmm9
-	movaps	0x20(%rdi),%xmm10
-	movaps	0x30(%rdi),%xmm11
-	movaps	0x40(%rdi),%xmm12
-	movaps	0x50(%rdi),%xmm13
-	movaps	0x60(%rdi),%xmm14
-	movaps	0x70(%rdi),%xmm15
+	movdqu	%xmm0,-0x80(%rdi)
+	movdqu	%xmm1,-0x70(%rdi)
+	movdqu	%xmm2,-0x60(%rdi)
+	movdqu	%xmm3,-0x50(%rdi)
+	movdqu	%xmm4,-0x40(%rdi)
+	movdqu	%xmm5,-0x30(%rdi)
+	movdqu	%xmm6,-0x20(%rdi)
+	movdqu	%xmm7,-0x10(%rdi)
+	movdqu	%xmm8,0x00(%rdi)
+	movdqu	%xmm9,0x10(%rdi)
+	movdqu	%xmm10,0x20(%rdi)
+	movdqu	%xmm11,0x30(%rdi)
+	movdqu	%xmm12,0x40(%rdi)
+	movdqu	%xmm13,0x50(%rdi)
+	movdqu	%xmm14,0x60(%rdi)
+	movdqu	%xmm15,0x70(%rdi)
 	.leafepilogue
-	.endfn	_loadxmm,globl,hidden
+	.endfn	__xmm_save,globl,hidden
+
+__xmm_load:
+	lea	-128(%rbp),%rdi
+	.leafprologue
+	movdqu	-0x80(%rdi),%xmm0
+	movdqu	-0x70(%rdi),%xmm1
+	movdqu	-0x60(%rdi),%xmm2
+	movdqu	-0x50(%rdi),%xmm3
+	movdqu	-0x40(%rdi),%xmm4
+	movdqu	-0x30(%rdi),%xmm5
+	movdqu	-0x20(%rdi),%xmm6
+	movdqu	-0x10(%rdi),%xmm7
+	movdqu	0x00(%rdi),%xmm8
+	movdqu	0x10(%rdi),%xmm9
+	movdqu	0x20(%rdi),%xmm10
+	movdqu	0x30(%rdi),%xmm11
+	movdqu	0x40(%rdi),%xmm12
+	movdqu	0x50(%rdi),%xmm13
+	movdqu	0x60(%rdi),%xmm14
+	movdqu	0x70(%rdi),%xmm15
+	.leafepilogue
+	.endfn	__xmm_load,globl,hidden