diff options
Diffstat (limited to 'cpukit/score/cpu/i386/cpu_asm.S')
| -rw-r--r-- | cpukit/score/cpu/i386/cpu_asm.S | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/cpukit/score/cpu/i386/cpu_asm.S b/cpukit/score/cpu/i386/cpu_asm.S index 9b395678b8..f3ef4e2c38 100644 --- a/cpukit/score/cpu/i386/cpu_asm.S +++ b/cpukit/score/cpu/i386/cpu_asm.S @@ -327,6 +327,49 @@ SYM (i386_Physical_to_logical): movl ecx,eax /* eax = ecx */ ret +/* + * int i386_Physical_to_real( + * void *address, + * uint16_t *segment, + * uint16_t *offset + * ); + * + * Fills segment:offest realmode pointer counted from thirty-two bit physical + * address. + * Returns 0 if unconvertible, 1 if successfuly converted. + */ + +.set PHYS_PTR_ARG, 4 +.set RM_PTR_SEG_ARG, 8 +.set RM_PTR_OFF_ARG, 12 + + PUBLIC (i386_Physical_to_real) + +SYM (i386_Physical_to_real): + movl PHYS_PTR_ARG(esp),eax + cmpl $0x10FFF0, eax + js 1f + movl $0, eax + ret +1: cmpl $0x100000, eax + js 2f + subl $0xFFFF0, eax + movl RM_PTR_OFF_ARG(esp), ecx + movw ax, (ecx) + movl RM_PTR_SEG_ARG(esp), ecx + movw $0xFFFF, (ecx) + movl $1, eax + ret +2: movl eax, edx + and $0xF, ax + movl RM_PTR_OFF_ARG(esp), ecx + movw ax, (ecx) + shrl $4, edx + movl RM_PTR_SEG_ARG(esp), ecx + movw dx, (ecx) + movl $1, eax + ret + END_CODE END |