Remove CPU speed detection

Tweak SMP startup

Author: IanSeyler

docs/README.md

@@ -183,7 +183,7 @@ The Pure64 information table is located at `0x0000000000005000` and ends at `0x0
 <tr><th>Memory Address</th><th>Variable Size</th><th>Name</th><th>Description</th></tr>
 <tr><td>0x5000</td><td>64-bit</td><td>ACPI</td><td>Address of the ACPI tables</td></tr>
 <tr><td>0x5008</td><td>32-bit</td><td>CPU_BSP_ID</td><td>APIC ID of the BSP</td></tr>
-<tr><td>0x5010</td><td>16-bit</td><td>CPU_SPEED</td><td>Speed of the CPUs in MegaHertz (<a href="http://en.wikipedia.org/wiki/Hertz">MHz</a>)</td></tr>
+<tr><td>0x500C - 0x5011</td><td>&nbsp;</td><td>&nbsp;</td><td>For future use</td></tr>
 <tr><td>0x5012</td><td>16-bit</td><td>CPU_CORES_ACTIVE</td><td>The number of CPU cores that were activated in the system</td></tr>
 <tr><td>0x5014</td><td>16-bit</td><td>CPU_CORES_DETECT</td><td>The number of CPU cores that were detected in the system</td></tr>
 <tr><td>0x5016</td><td>8-bit</td><td>CPU_MEM_PHYSICAL</td><td>The number of bits that are valid for a physical address</td></tr>

src/init/smp.asm

@@ -9,13 +9,16 @@
 init_smp:
 	; Check if we want the AP's to be enabled.. if not then skip to end
 	cmp byte [cfg_smpinit], 1	; Check if SMP should be enabled
-	jne noMP			; If not then skip SMP init
+	jne init_smp_done		; If not then skip SMP init
 
+	; Check if multiple CPUs were detected via the ACPI tables
+	xor ecx, ecx
+	mov cx, [p_cpu_detected]
+	cmp cx, 1
+	je init_smp_done		; Only 1 CPU detected, skip SMP init
 	mov edx, [p_BSP]		; Get the BSP APIC ID
 	mov esi, IM_DetectedCoreIDs	; List of 32-bit APIC IDs
 	xor eax, eax
-	xor ecx, ecx
-	mov cx, [p_cpu_detected]
 smp_send_INIT:
 	cmp cx, 0
 	je smp_send_INIT_done
@@ -115,24 +118,7 @@ smp_send_SIPI_done:
 	mov eax, 10000		; 10000 microseconds (10ms)
 	call timer_delay
 
-noMP:
-
-;	; Calculate base speed of CPU
-;	cpuid
-;	xor edx, edx
-;	xor eax, eax
-;	rdtsc
-;	push rax
-;	mov rax, 1024		; 1024 microseconds (1ms)
-;	call timer_delay
-;	rdtsc
-;	pop rdx
-;	sub rax, rdx
-;	xor edx, edx
-;	mov rcx, 1024
-;	div rcx
-;	mov [p_cpu_speed], ax
-
+init_smp_done:
 	ret
 
 

src/pure64.asm

@@ -784,9 +784,7 @@ pde_end:
 	mov eax, [p_BSP]
 	stosd
 
-	mov di, 0x5010
-	mov ax, [p_cpu_speed]
-	stosw
+	mov di, 0x5012
 	mov ax, [p_cpu_activated]
 	stosw
 	mov ax, [p_cpu_detected]

src/sysvar.asm

@@ -50,7 +50,6 @@ p_mem_amount:		equ SystemVariables + 0x84	; in MiB
 p_HPET_Frequency:	equ SystemVariables + 0x88
 
 ; DW - Starting at offset 0x100, increments by 2
-p_cpu_speed:		equ SystemVariables + 0x100
 p_cpu_activated:	equ SystemVariables + 0x102
 p_cpu_detected:		equ SystemVariables + 0x104
 p_PCIECount:		equ SystemVariables + 0x106