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Diffstat (limited to 'reference/C/CONTRIB/SNIP/cpucheck.asm')
| -rwxr-xr-x | reference/C/CONTRIB/SNIP/cpucheck.asm | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/reference/C/CONTRIB/SNIP/cpucheck.asm b/reference/C/CONTRIB/SNIP/cpucheck.asm new file mode 100755 index 0000000..f5ae682 --- /dev/null +++ b/reference/C/CONTRIB/SNIP/cpucheck.asm @@ -0,0 +1,78 @@ + page 55, 132
+
+; FUNCTION: cpu_check
+;
+; Attempt to discover the type of CPU. Use MASM 5.1 or greater.
+; Returns 86 for 8088/8086, 286 for 80286, 386 for 80386/80486.
+;
+; Requires MASM 5.1 or later or equivalent
+;
+; Assemble with: MASM /Mx /z ...
+; TASM /jMASM /mx /z ...
+;
+
+% .MODEL memodel,C ;Add model support via
+ ;command line macros, e.g.
+ ;MASM /Dmemodel=LARGE
+
+ .CODE
+;
+; int cpu_check(void) - returns 86, 186, 286, 386
+;
+
+ PUBLIC cpu_check
+
+cpu_check PROC USES BX
+ pushf
+ xor ax,ax ; zero ax
+ push ax
+ popf ; try to put 0 into flags
+ pushf
+ pop ax ; see what went in flags
+ and ax,0f000h ; mask off high flag bits
+ cmp ax,0f000h ; was high nibble ones
+ je _86 ; is 8086 or 8088
+ push sp ; see if sp is updated
+ pop bx ; before or after it is
+ cmp bx,sp ; pushed
+ jne _186
+ mov ax,0f000h ; try to set high bits
+ push ax
+ popf ; in the flags
+ pushf
+ pop ax ; look at actual flags
+ and ax,0f000h ; any high bits set?
+ je _286 ; is 80286
+_386:
+ .386 ; enable 386 instructions
+
+ pushfd ; save extended flags
+ mov eax,040000h
+ push eax ; push 40000h onto stack
+ popfd ; pop extended flags
+ pushfd ; push extended flags
+ pop eax ; put in eax
+ and eax,040000h ; is bit 18 set?
+ jne _486 ; yes, it's a 486
+ mov ax,386 ; no, it's a 386
+ jmp _386x
+_486:
+ mov ax,486
+_386x:
+ popfd ; clean the stack
+ jmp ccexit
+_286:
+ mov ax,286 ; is an 80286
+ jmp ccexit
+_186:
+ mov ax,186 ; is an 80188/80186
+ jmp ccexit
+_86:
+ mov ax,86 ; is an 8088/8086
+ccexit:
+ popf ; restore original flags
+ ret ; return
+
+cpu_check ENDP
+
+ end
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