From e3241e35cc133961fae184753d3e6cf2b199d752 Mon Sep 17 00:00:00 2001
From: Abdur-Rahman Mansoor <armansoor@missingno.dev>
Date: Mon, 22 Jul 2024 14:19:54 -0400
Subject: [PATCH] perf(size): remove useless pow2 implementation

---
 drivers/nvme/nvme.asm | 41 ++++++++++-------------------------------
 1 file changed, 10 insertions(+), 31 deletions(-)

diff --git a/drivers/nvme/nvme.asm b/drivers/nvme/nvme.asm
index f68f675..c61842f 100644
--- a/drivers/nvme/nvme.asm
+++ b/drivers/nvme/nvme.asm
@@ -690,12 +690,7 @@ proc nvme_readwrite stdcall, ns:dword, buf:dword, start_sector:qword, numsectors
 	jz 	.dptr_fail
 
 	DEBUGF  DBG_INFO, "PRP1: %x, PRP2: %x\n", [ebx], [ebx + 4]
-
 	mov 	eax, dword [start_sector]
-	mov 	ecx, dword [esi + NSINFO.lbads]
-	xor 	edx, edx
-	div 	ecx
-	DEBUGF  DBG_INFO, "sector start: %u\n", eax
 
 	; According to the NVMe specification, the NLB field in the I/O read and write
 	; commands is a 0-based value (i.e., 0 is equivalant to 1, 1 is equivalant to 2, ...)
@@ -1110,11 +1105,13 @@ proc nvme_init stdcall, pci:dword
 	mov 	dword [ebx + NSINFO.capacity + 4], eax 
 	;DEBUGF  DBG_INFO, "nvme%un%u: Namespace Size: %u + %u logical blocks\n", [esi + pcidev.num], [esi + pcidev.nsid], [edi + IDENTN.nsze], [edi + IDENTN.nsze + 4]
 	;DEBUGF  DBG_INFO, "nvme%un%u: Namespace Capacity: %u + %u logical blocks\n", [esi + pcidev.num], [esi + pcidev.nsid], [edi + IDENTN.ncap], [edi + IDENTN.ncap + 4]
-	mov 	eax, dword [edi + IDENTN.lbaf0]
-	shr 	eax, 16 ; Get LBADS
-	and 	eax, 0xff
-	stdcall pow2, eax
-	;DEBUGF  DBG_INFO, "nvme%un%u: Namespace LBA Data Size: %u\n", [esi + pcidev.num], [esi + pcidev.nsid], eax
+	mov 	ecx, dword [edi + IDENTN.lbaf0]
+	shr 	ecx, 16 ; Get LBADS
+	and 	ecx, 0xff
+	dec 	ecx
+	mov 	eax, 2
+	shl 	eax, cl
+	DEBUGF  DBG_INFO, "nvme%un%u: Namespace LBA Data Size: %u\n", [esi + pcidev.num], [esi + pcidev.nsid], eax
 
 	; KolibriOS only supports a LBADS of 512, so if it's a higher value then we
 	; have to ignore this namespace
@@ -1128,7 +1125,7 @@ proc nvme_init stdcall, pci:dword
 	div 	ecx
 	mov 	dword [ebx + NSINFO.pg_sectors], eax
 	invoke  KernelFree, edi
-	if 1
+	if 0
 		invoke  KernelAlloc, 0x6000
 		test 	eax, eax
 		jz 	.exit_fail
@@ -1138,6 +1135,7 @@ proc nvme_init stdcall, pci:dword
 		jz 	.exit_fail
 		mov 	edx, NVM_CMD_READ
 		mov 	dword [eax], 25
+		add 	edi, 0x5
 		stdcall nvme_readwrite, [esi + pcidev.nsinfo], edi, 0x1000, 0, eax
 	        DEBUGF  DBG_INFO, "STRING: %s\n", edi
 		add 	edi, 0x2000
@@ -1303,25 +1301,6 @@ proc sqytdbl_write stdcall, pci:dword, y:word, cmd:dword
 
 endp
 
-; Calculates 2^x
-proc pow2 stdcall, x:byte 
-
-	push 	ecx
-	mov 	cl, [x]
-	xor 	eax, eax
-	inc 	eax
-	test 	cl, cl
-	jnz 	@f
-	pop 	ecx
-	ret
-
-@@:
-	shl 	eax, cl
-	pop 	ecx
-	ret
-	
-endp
-
 proc nvme_cmd_wait stdcall, pci:dword, y:dword, cid:word
 	
 	push 	esi
@@ -1488,7 +1467,7 @@ align 4
 		dd 	 0 ; no close function
 		dd 	 0 ; no closemedia function
 		dd 	 nvme_query_media
-		dd 	 0
+		dd 	 nvme_read
 		dd 	 0 ; no write function (for now)
 		dd 	 0 ; no flush function
 		dd 	 0 ; use default cache size