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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/i386/math-emu/reg_norm.S
downloadconfigs-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/i386/math-emu/reg_norm.S')
-rw-r--r--arch/i386/math-emu/reg_norm.S147
1 files changed, 147 insertions, 0 deletions
diff --git a/arch/i386/math-emu/reg_norm.S b/arch/i386/math-emu/reg_norm.S
new file mode 100644
index 00000000000..8b6352efcee
--- /dev/null
+++ b/arch/i386/math-emu/reg_norm.S
@@ -0,0 +1,147 @@
+/*---------------------------------------------------------------------------+
+ | reg_norm.S |
+ | |
+ | Copyright (C) 1992,1993,1994,1995,1997 |
+ | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, |
+ | Australia. E-mail billm@suburbia.net |
+ | |
+ | Normalize the value in a FPU_REG. |
+ | |
+ | Call from C as: |
+ | int FPU_normalize(FPU_REG *n) |
+ | |
+ | int FPU_normalize_nuo(FPU_REG *n) |
+ | |
+ | Return value is the tag of the answer, or-ed with FPU_Exception if |
+ | one was raised, or -1 on internal error. |
+ | |
+ +---------------------------------------------------------------------------*/
+
+#include "fpu_emu.h"
+
+
+.text
+ENTRY(FPU_normalize)
+ pushl %ebp
+ movl %esp,%ebp
+ pushl %ebx
+
+ movl PARAM1,%ebx
+
+ movl SIGH(%ebx),%edx
+ movl SIGL(%ebx),%eax
+
+ orl %edx,%edx /* ms bits */
+ js L_done /* Already normalized */
+ jnz L_shift_1 /* Shift left 1 - 31 bits */
+
+ orl %eax,%eax
+ jz L_zero /* The contents are zero */
+
+ movl %eax,%edx
+ xorl %eax,%eax
+ subw $32,EXP(%ebx) /* This can cause an underflow */
+
+/* We need to shift left by 1 - 31 bits */
+L_shift_1:
+ bsrl %edx,%ecx /* get the required shift in %ecx */
+ subl $31,%ecx
+ negl %ecx
+ shld %cl,%eax,%edx
+ shl %cl,%eax
+ subw %cx,EXP(%ebx) /* This can cause an underflow */
+
+ movl %edx,SIGH(%ebx)
+ movl %eax,SIGL(%ebx)
+
+L_done:
+ cmpw EXP_OVER,EXP(%ebx)
+ jge L_overflow
+
+ cmpw EXP_UNDER,EXP(%ebx)
+ jle L_underflow
+
+L_exit_valid:
+ movl TAG_Valid,%eax
+
+ /* Convert the exponent to 80x87 form. */
+ addw EXTENDED_Ebias,EXP(%ebx)
+ andw $0x7fff,EXP(%ebx)
+
+L_exit:
+ popl %ebx
+ leave
+ ret
+
+
+L_zero:
+ movw $0,EXP(%ebx)
+ movl TAG_Zero,%eax
+ jmp L_exit
+
+L_underflow:
+ /* Convert the exponent to 80x87 form. */
+ addw EXTENDED_Ebias,EXP(%ebx)
+ push %ebx
+ call arith_underflow
+ pop %ebx
+ jmp L_exit
+
+L_overflow:
+ /* Convert the exponent to 80x87 form. */
+ addw EXTENDED_Ebias,EXP(%ebx)
+ push %ebx
+ call arith_overflow
+ pop %ebx
+ jmp L_exit
+
+
+
+/* Normalise without reporting underflow or overflow */
+ENTRY(FPU_normalize_nuo)
+ pushl %ebp
+ movl %esp,%ebp
+ pushl %ebx
+
+ movl PARAM1,%ebx
+
+ movl SIGH(%ebx),%edx
+ movl SIGL(%ebx),%eax
+
+ orl %edx,%edx /* ms bits */
+ js L_exit_nuo_valid /* Already normalized */
+ jnz L_nuo_shift_1 /* Shift left 1 - 31 bits */
+
+ orl %eax,%eax
+ jz L_exit_nuo_zero /* The contents are zero */
+
+ movl %eax,%edx
+ xorl %eax,%eax
+ subw $32,EXP(%ebx) /* This can cause an underflow */
+
+/* We need to shift left by 1 - 31 bits */
+L_nuo_shift_1:
+ bsrl %edx,%ecx /* get the required shift in %ecx */
+ subl $31,%ecx
+ negl %ecx
+ shld %cl,%eax,%edx
+ shl %cl,%eax
+ subw %cx,EXP(%ebx) /* This can cause an underflow */
+
+ movl %edx,SIGH(%ebx)
+ movl %eax,SIGL(%ebx)
+
+L_exit_nuo_valid:
+ movl TAG_Valid,%eax
+
+ popl %ebx
+ leave
+ ret
+
+L_exit_nuo_zero:
+ movl TAG_Zero,%eax
+ movw EXP_UNDER,EXP(%ebx)
+
+ popl %ebx
+ leave
+ ret