X-Git-Url: https://git.distorted.org.uk/~mdw/catacomb/blobdiff_plain/a3ad4421ce9e122bc9079ffc6e60f45b1b06c1d7..e3da9aaf8fcb82c3c253bcdd165273eecc689b51:/base/dispatch-x86ish.S

diff --git a/base/dispatch-x86ish.S b/base/dispatch-x86ish.S
index 2c267b62..67ec05e6 100644
--- a/base/dispatch-x86ish.S
+++ b/base/dispatch-x86ish.S
@@ -44,48 +44,51 @@ FUNC(dispatch_x86ish_cpuid)
 	// return zero if we can; otherwise fill with zero and return -1.
 
 #if CPUFAM_X86
+#  define OUT edi
 	pushreg	ebx
 	pushreg	edi
-	mov	edi, [esp + 12]
-	mov	eax, [esp + 16]
-	mov	ecx, [esp + 20]
-#  define OUT edi
+	mov	OUT, [SP + 12]
+	mov	eax, [SP + 16]
+	mov	ecx, [SP + 20]
 #endif
 #if CPUFAM_AMD64 && ABI_SYSV
+#  define OUT rdi
 	pushreg	rbx
 	mov	eax, esi
 	mov	ecx, edx
-#  define OUT rdi
 #endif
 #if CPUFAM_AMD64 && ABI_WIN
+#  define OUT r9
 	pushreg	rbx
-	mov	r9, rcx
+	mov	OUT, rcx
 	mov	eax, edx
 	mov	ecx, r8d
-#  define OUT r9
 #endif
   endprologue
 
 	// First, check that this is even a thing, using the complicated
-	// dance with the flags register.
+	// dance with the flags register.  This is unnecessary on AMD64,
+	// which postdates the introduction of `cpuid'.
+#if CPUFAM_X86
 	pushf
-	pop	R_d(r)			// current flags in d
+	pop	DX			// current flags in d
 
-	or	R_d(r), EFLAGS_ID	// force the id bit on and check it
-	push	R_d(r)
+	or	DX, EFLAGS_ID		// force the id bit on and check it
+	push	DX
 	popf
 	pushf
-	pop	R_d(r)
+	pop	DX
 	test	edx, EFLAGS_ID
 	jz	8f
 
-	and	R_d(r), ~EFLAGS_ID	// force the id bit off and check it
-	push	R_d(r)
+	and	DX, ~EFLAGS_ID		// force the id bit off and check it
+	push	DX
 	popf
 	pushf
-	pop	R_d(r)
+	pop	DX
 	test	edx, EFLAGS_ID
 	jnz	8f
+#endif
 
 	// OK, that seemed to work.
 	cpuid
@@ -108,6 +111,7 @@ FUNC(dispatch_x86ish_cpuid)
 	ret
 
 	// Failed.
+#if CPUFAM_X86
 8:	xor	eax, eax
 	mov	[OUT + 0], eax
 	mov	[OUT + 4], eax
@@ -115,6 +119,9 @@ FUNC(dispatch_x86ish_cpuid)
 	mov	[OUT + 12], eax
 	mov	eax, -1
 	jmp	9b
+#endif
+
+#undef OUT
 ENDFUNC
 
 ///--------------------------------------------------------------------------
@@ -124,33 +131,130 @@ FUNC(dispatch_x86ish_xmmregisters_p)
 	// Enter with no arguments.  Return nonzero if the XMM registers are
 	// usable.
 
-	pushreg	R_bp(r)
+	pushreg	BP
 	setfp
 	stalloc	512
-	and	R_sp(r), ~15
+	and	SP, ~15
   endprologue
 
 	// Save the floating point and SIMD registers, and try to clobber
 	// xmm0.
-	fxsave	[R_sp(r)]
-	mov	eax, [R_sp(r) + 160]
-	xor	dword ptr [R_sp(r) + 160], 0xaaaa5555
-	fxrstor	[R_sp(r)]
+	lea	DX, [SP + 160]
+	fxsave	[SP]
+	mov	eax, [DX]
+	xor	dword ptr [DX], 0xaaaa5555
+	fxrstor	[SP]
 
 	// Save them again, and read back the low word of xmm0.  Undo the
 	// clobbering and restore.
-	fxsave	[R_sp(r)]
-	mov	ecx, [R_sp(r) + 160]
-	mov	[R_sp(r) + 160], eax
-	fxrstor	[R_sp(r)]
+	fxsave	[SP]
+	mov	ecx, [DX]
+	mov	[DX], eax
+	fxrstor	[SP]
 
 	// The register are live if we read different things.
 	xor	eax, ecx
 
 	// Done.
 	dropfp
-	popreg	R_bp(r)
+	popreg	BP
+	ret
+ENDFUNC
+
+///--------------------------------------------------------------------------
+/// Checking extended control registers.
+
+FUNC(dispatch_x86ish_xgetbv)
+	// Call with two arguments: a pointer Z_OUT to 8 bytes of output space, and
+	// a 32-bit integer C.  Read the 64-bit value of XCR(C), and store it
+	// at Z_OUT.
+
+#if CPUFAM_X86
+#  define Z_OUT edi
+	pushreg	edi
+	mov	Z_OUT, [esp + 8]
+	mov	ecx, [esp + 12]
+#endif
+#if CPUFAM_AMD64 && ABI_SYSV
+#  define Z_OUT rdi
+	mov	ecx, esi
+#endif
+#if CPUFAM_AMD64 && ABI_WIN
+#  define Z_OUT r8
+	mov	r8, rcx
+	mov	ecx, edx
+#endif
+  endprologue
+
+	xgetbv
+	mov	[Z_OUT + 0], eax
+	mov	[Z_OUT + 4], edx
+
+#if CPUFAM_X86
+	popreg	edi
+#endif
 	ret
+
+#undef Z_OUT
+ENDFUNC
+
+///--------------------------------------------------------------------------
+/// Checking `rdrand'.
+
+FUNC(dispatch_x86ish_rdrand)
+	// Enter with two arguments: a code OP requesting either `rdrand' (0)
+	// or `rdseed' (1), and a pointer X_OUT to a 32-bit word.  Try to
+	// generate a random word using the requested instruction'.  If
+	// successful, set *X_OUT to the generated word, and return zero;
+	// otherwise, return -1.
+
+#if CPUFAM_X86
+#  define OP eax
+#  define X_OUT edx
+#  define COUNT ecx
+	mov	OP, [SP + 4]
+	mov	X_OUT, [SP + 8]
+#endif
+#if CPUFAM_AMD64 && ABI_SYSV
+#  define OP edi
+#  define X_OUT rsi
+#  define COUNT ecx
+#endif
+#if CPUFAM_AMD64 && ABI_WIN
+#  define OP rcx
+#  define X_OUT rdx
+#  define COUNT r8d
+#endif
+  endprologue
+
+	cmp	OP, 0
+	mov	COUNT, 16		// fairly persistent
+	jne	1f
+
+0:	rdrand	eax
+	jc	9f
+	dec	COUNT
+	jnz	0b
+	jmp	8f
+
+1:	rdseed	eax
+	jc	9f
+	dec	COUNT
+	jnz	1b
+	jmp	8f
+
+	// Failed to come up with a random value.
+8:	mov	eax, -1
+	ret
+
+	// Success.
+9:	mov	[X_OUT], eax
+	xor	eax, eax
+	ret
+
+#undef X_OUT
+#undef COUNT
+
 ENDFUNC
 
 ///----- That's all, folks --------------------------------------------------