From 1758da9285a0abcd814be415ed8262b7c117ef3e Mon Sep 17 00:00:00 2001
From: ceriel <none@none>
Date: Mon, 27 Nov 1989 16:19:16 +0000
Subject: [PATCH] Added fp8087.s

---
 mach/i86/libem/LIST     |   2 +-
 mach/i86/libem/fp8087.s | 518 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 519 insertions(+), 1 deletion(-)
 create mode 100644 mach/i86/libem/fp8087.s

diff --git a/mach/i86/libem/LIST b/mach/i86/libem/LIST
index 5288b2173..aeb8783d3 100644
--- a/mach/i86/libem/LIST
+++ b/mach/i86/libem/LIST
@@ -17,7 +17,7 @@ dvi4.s
 dvu.s
 dvu4.s
 exg.s
-fakfp.s
+fp8087.s
 gto.s
 iaar.s
 ilar.s
diff --git a/mach/i86/libem/fp8087.s b/mach/i86/libem/fp8087.s
new file mode 100644
index 000000000..d9635059f
--- /dev/null
+++ b/mach/i86/libem/fp8087.s
@@ -0,0 +1,518 @@
+.define .adf4, .adf8, .sbf4, .sbf8, .mlf4, .mlf8, .dvf4, .dvf8
+.define .ngf4, .ngf8, .fif4, .fif8, .fef4, .fef8
+.define .cif4, .cif8, .cuf4, .cuf8, .cfi, .cfu, .cff4, .cff8
+.define .cmf4, .cmf8
+.sect .text; .sect .rom; .sect .data; .sect .bss
+
+!	$Header$
+
+!	Implement interface to floating point package for Intel 8087
+
+	.sect .rom
+one:
+	.data2	1
+two:
+	.data2	2
+bigmin:
+	.data4 	-2147483648
+
+	.sect .text
+.adf4:
+	mov	bx,sp
+	wait
+	flds	2(bx)
+	fadds	6(bx)
+	fstps	6(bx)
+	wait
+	ret
+.adf8:
+	mov	bx,sp
+	wait
+	fldd	2(bx)
+	faddd	10(bx)
+	fstpd	10(bx)
+	wait
+	ret
+
+.sbf4:
+	mov	bx,sp
+	wait
+	flds	6(bx)
+	fsubs	2(bx)
+	fstps	6(bx)
+	wait
+	ret
+
+.sbf8:
+	mov	bx,sp
+	wait
+	fldd	10(bx)
+	fsubd	2(bx)
+	fstpd	10(bx)
+	wait
+	ret
+
+.mlf4:
+	mov	bx,sp
+	wait
+	flds	2(bx)
+	fmuls	6(bx)
+	fstps	6(bx)
+	wait
+	ret
+.mlf8:
+	mov	bx,sp
+	wait
+	fldd	2(bx)
+	fmuld	10(bx)
+	fstpd	10(bx)
+	wait
+	ret
+
+.dvf4:
+	mov	bx,sp
+	wait
+	flds	6(bx)
+	fdivs	2(bx)
+	fstps	6(bx)
+	wait
+	ret
+
+.dvf8:
+	mov	bx,sp
+	wait
+	fldd	10(bx)
+	fdivd	2(bx)
+	fstpd	10(bx)
+	wait
+	ret
+
+.ngf4:
+	mov	bx,sp
+	wait
+	flds	2(bx)
+	fchs
+	fstps	2(bx)
+	wait
+	ret
+
+.ngf8:
+	mov	bx,sp
+	wait
+	fldd	2(bx)
+	fchs
+	fstpd	2(bx)
+	wait
+	ret
+
+.fif4:
+	mov	bx,sp
+	push	bx		! make room for FP status word
+	wait
+	flds	4(bx)
+	fmuls	8(bx)		! multiply
+	fld	st		! copy result
+	ftst			! test sign; handle negative separately
+	fstsw	-2(bx)
+	wait
+	mov	ax,-2(bx)
+	sahf			! result of test in condition codes
+	jb	1f
+	frndint			! this one rounds (?)
+	fcom	st(1)		! compare with original; if <=, then OK
+	fstsw	-2(bx)
+	wait
+	mov	ax,-2(bx)
+	sahf
+	jbe	2f
+	fisubs	(one)		! else subtract 1
+	jmp	2f
+1:				! here, negative case
+	frndint			! this one rounds (?)
+	fcom	st(1)		! compare with original; if >=, then OK
+	fstsw	-2(bx)
+	wait
+	mov	ax,-2(bx)
+	sahf
+	jae	2f
+	fiadds	(one)		! else add 1
+2:
+	fsub	st(1),st	! subtract integer part
+	mov	bx,2(bx)
+	fstps	(bx)
+	fstps	4(bx)
+	wait
+	pop	bx
+	ret
+
+.fif8:
+	mov	bx,sp
+	push	bx		! make room for FP status word
+	wait
+	fldd	4(bx)
+	fmuld	12(bx)		! multiply
+	fld	st		! and copy result
+	ftst			! test sign; handle negative separately
+	fstsw	-2(bx)
+	wait
+	mov	ax,-2(bx)
+	sahf			! result of test in condition codes
+	jb	1f
+	frndint			! this one rounds (?)
+	fcom	st(1)		! compare with original; if <=, then OK
+	fstsw	-2(bx)
+	wait
+	mov	ax,-2(bx)
+	sahf
+	jbe	2f
+	fisubs	(one)		! else subtract 1
+	jmp	2f
+1:				! here, negative case
+	frndint			! this one rounds (?)
+	fcom	st(1)		! compare with original; if >=, then OK
+	fstsw	-2(bx)
+	wait
+	mov	ax,-2(bx)
+	sahf
+	jae	2f
+	fiadds	(one)		! else add 1
+2:
+	fsub	st(1),st	! subtract integer part
+	mov	bx,2(bx)
+	fstpd	(bx)
+	fstpd	8(bx)
+	wait
+	pop	bx
+	ret
+
+.fef4:
+				! this could be simpler, if only the
+				! fxtract instruction was emulated properly
+	mov	bx,sp
+	mov	ax,6(bx)
+	and	ax,077600
+	je	1f		! zero exponent
+	mov	cx,7
+	shr	ax,cl
+	sub	ax,126
+	mov	cx,ax		! exponent in cx
+	mov	ax,6(bx)
+	and	ax,0100177
+	or	ax,0037400	! load -1 exponent
+	mov	dx,4(bx)
+	mov	bx,2(bx)
+	mov	4(bx),ax
+	mov	2(bx),dx
+	mov	(bx),cx
+	ret
+1:				! we get here on zero exp
+	mov	ax,6(bx)
+	and	ax,0177
+	mov	6(bx),ax
+	or	ax,4(bx)
+	jne	1f		! zero result
+	xor	ax,ax
+	mov	bx,2(bx)
+	mov	(bx),ax
+	mov	2(bx),ax
+	mov	4(bx),ax
+	ret
+1:				! otherwise unnormalized number
+	mov	cx,6(bx)
+	mov	dx,cx
+	and	cx,0x8000
+	mov	ax,-125
+2:
+	test	dx,0x80
+	jne	1f
+	dec	ax
+	shl	4(bx),1
+	rcl	dx,1
+	or	dx,cx
+	jmp	2b
+1:
+	mov	cx,4(bx)
+	mov	bx,2(bx)
+	mov	(bx),ax
+	mov	2(bx),cx
+	and	dx,0100177
+	or	dx,0037400	! load -1 exponent
+	mov	4(bx),dx
+	ret
+
+.fef8:
+				! this could be simpler, if only the
+				! fxtract instruction was emulated properly
+	mov	bx,sp
+	mov	ax,10(bx)
+	and	ax,077760
+	je	1f		! zero exponent
+	mov	cx,4
+	shr	ax,cl
+	sub	ax,1022
+	mov	cx,ax		! exponent in cx
+	mov	ax,10(bx)
+	and	ax,0100017
+	or	ax,0037740	! load -1 exponent
+	push	8(bx)
+	push	6(bx)
+	push	4(bx)
+	mov	bx,2(bx)
+	pop	2(bx)
+	pop	4(bx)
+	pop	6(bx)
+	mov	8(bx),ax
+	mov	(bx),cx
+	ret
+1:				! we get here on zero exp
+	mov	ax,10(bx)
+	and	ax,017
+	mov	10(bx),ax
+	or	ax,8(bx)
+	or	ax,6(bx)
+	or	ax,4(bx)
+	jne	1f		! zero result
+	xor	ax,ax
+	mov	bx,2(bx)
+	mov	(bx),ax
+	mov	2(bx),ax
+	mov	4(bx),ax
+	mov	6(bx),ax
+	mov	8(bx),ax
+	ret
+1:				! otherwise unnormalized number
+	mov	cx,10(bx)
+	mov	dx,cx
+	and	cx,0x8000
+	mov	ax,-1021
+2:
+	test	dx,0x10
+	jne	1f
+	dec	ax
+	shl	4(bx),1
+	rcl	6(bx),1
+	rcl	8(bx),1
+	rcl	dx,1
+	or	dx,cx
+	jmp	2b
+1:
+	and	dx,0100017
+	or	dx,0037740	! load -1 exponent
+	mov	cx,8(bx)
+	push	6(bx)
+	push	4(bx)
+	mov	bx,2(bx)
+	mov	(bx),ax
+	mov	8(bx),dx
+	mov	6(bx),cx
+	pop	2(bx)
+	pop	4(bx)
+	ret
+
+.cif4:
+	mov	bx,sp
+	cmp	2(bx),2
+	jne	1f
+	filds	4(bx)
+	fstps	2(bx)
+	wait
+	ret
+1:
+	fildl	4(bx)
+	fstps	4(bx)
+	wait
+	ret
+
+.cif8:
+	mov	bx,sp
+	cmp	2(bx),2
+	jne	1f
+	filds	4(bx)
+	fstpd	2(bx)
+	wait
+	ret
+1:
+	fildl	4(bx)
+	fstpd	2(bx)
+	wait
+	ret
+
+.cuf4:
+	mov	bx,sp
+	cmp	2(bx),2
+	jne	1f
+	mov	ax,4(bx)
+	mov	2(bx),ax
+	mov	4(bx),0
+	fildl	2(bx)
+	fstps	2(bx)
+	wait
+	ret
+1:
+	fildl	4(bx)
+	cmp	6(bx),0
+	jge	1f
+2:
+	fisubl	(bigmin)
+	fisubl	(bigmin)
+1:
+	fstps	4(bx)
+	wait
+	ret
+
+.cuf8:
+	mov	bx,sp
+	cmp	2(bx),2
+	jne	1f
+	mov	6(bx),0
+1:
+	fildl	4(bx)
+	cmp	6(bx),0
+	jge	1f
+2:
+	fisubl	(bigmin)
+	fisubl	(bigmin)
+1:
+	fstpd	2(bx)
+	wait
+	ret
+
+.cfi:
+	mov	bx,sp
+	push	bx
+	fstcw	-2(bx)
+	wait
+	mov	dx,-2(bx)
+	or	-2(bx),0xc00	! truncating mode
+	wait
+	fldcw	-2(bx)
+	pop	ax
+	cmp	4(bx),4
+	jne	2f
+				! loc 4 loc ? cfi
+	flds	6(bx)
+	fistpl	6(bx)
+	wait
+	cmp	2(bx),2
+	jne	1f
+	mov	ax,6(bx)
+1:
+	mov	4(bx),dx
+	wait
+	fldcw	4(bx)
+	ret
+2:
+				! loc 8 loc ? cfi
+	fldd	6(bx)
+	fistpl	10(bx)
+	wait
+	cmp	2(bx),2
+	jne	1b
+	mov	ax,10(bx)
+	jmp	1b
+
+.cfu:
+	mov	bx,sp
+	push	bx
+	fstcw	-2(bx)
+	wait
+	mov	dx,-2(bx)
+	or	-2(bx),0xc00	! truncating mode
+	wait
+	fldcw	-2(bx)
+	pop	ax
+	cmp	4(bx),4
+	jne	2f
+				! loc 4 loc ? cfu
+	flds	6(bx)
+	fabs			! ???
+	fistpl	6(bx)
+	wait
+	cmp	2(bx),2
+	jne	1f
+	mov	ax,6(bx)
+1:
+	mov	4(bx),dx
+	wait
+	fldcw	4(bx)
+	ret
+2:
+				! loc 8 loc ? cfu
+	fldd	6(bx)
+	fabs			! ???
+	fistpl	10(bx)
+	wait
+	cmp	2(bx),2
+	jne	1b
+	mov	ax,10(bx)
+	jmp	1b
+
+.cff4:
+	mov	bx,sp
+	wait
+	fldd	2(bx)
+	fstcw	2(bx)
+	wait
+	mov	dx,2(bx)
+	and	2(bx),0xf3ff	! set to rounding mode
+	wait
+	fldcw	2(bx)
+	fstps	6(bx)
+	mov	2(bx),dx
+	wait
+	fldcw	2(bx)
+	wait
+	ret
+
+.cff8:
+	mov	bx,sp
+	wait
+	flds	2(bx)
+	fstpd	2(bx)
+	wait
+	ret
+
+.cmf4:
+	mov	bx,sp
+	push	bx		! room for 8087 status word
+	xor	cx,cx
+	flds	6(bx)
+	flds	2(bx)
+	fcompp			! compare and pop operands
+	fstsw	-2(bx)
+	wait
+	mov	ax,-2(bx)
+	sahf
+	je	1f
+	jb	2f
+	dec	cx
+	jmp	1f
+2:
+	inc	cx
+1:
+	mov	ax,cx
+	pop	bx
+	ret
+
+
+.cmf8:
+	mov	bx,sp
+	push	bx		! room for 8087 status word
+	xor	cx,cx
+	fldd	10(bx)
+	fldd	2(bx)
+	fcompp			! compare and pop operands
+	fstsw	-2(bx)
+	wait
+	mov	ax,-2(bx)
+	sahf
+	je	1f
+	jb	2f
+	dec	cx
+	jmp	1f
+2:
+	inc	cx
+1:
+	mov	ax,cx
+	pop	bx
+	ret