From 39dcfd2edc3b139e914370cd15fea37a91bff7de Mon Sep 17 00:00:00 2001
From: Abdur-Rahman Mansoor <armansoor@missingno.dev>
Date: Tue, 23 Jul 2024 14:10:42 -0400
Subject: [PATCH] perf: remove some unneeded code bloat

---
 drivers/nvme/nvme.asm | 67 +++++++++++++++++--------------------------
 drivers/nvme/nvme.inc |  3 +-
 2 files changed, 27 insertions(+), 43 deletions(-)

diff --git a/drivers/nvme/nvme.asm b/drivers/nvme/nvme.asm
index 6f3d8e9..f8208cd 100644
--- a/drivers/nvme/nvme.asm
+++ b/drivers/nvme/nvme.asm
@@ -565,48 +565,48 @@ endp
 
 proc alloc_dptr stdcall, ns:dword, prps_ptr:dword, numsectors:dword, prp_list_ptr:dword, buf:dword
 
-	push 	esi edi
+	push 	ebx esi edi
+	mov 	esi, [ns]
+
 	; the pointer to our PRP list (virtual), needed so
 	; that the caller can free the PRP list afterwards
 	mov 	edi, [prp_list_ptr]
 	mov 	dword [edi], 0
 
 	mov 	edi, [prps_ptr]
-	mov 	dword [edi], 0 ; PRP1 default value
 	mov 	dword [edi + 4], 0 ; PRP2 default value
 	mov 	eax, [buf]
 	invoke  GetPhysAddr
 	mov 	dword [edi], eax
-	mov 	edx, [numsectors]
+	mov 	cl, byte [esi + NSINFO.lbads]
+	mov 	ebx, PAGE_SIZE
+	shr 	ebx, cl
 	mov 	eax, edx
-	mov 	[numsectors], 0
-	cmp 	eax, dword [esi + NSINFO.pg_sectors]
+	cmp 	eax, ebx
 	jbe 	@f
-	sub 	eax, dword [esi + NSINFO.pg_sectors]
-	mov 	[numsectors], eax
+	sub 	eax, ebx
 
 @@:
-
-	mov 	esi, [ns]
-	mov 	eax, dword [esi + NSINFO.pg_sectors]
+	mov 	edx, [numsectors]
 
 	; is the buffer offset portion equal to 0?
-	mov 	ecx, [buf]
-	and 	ecx, PAGE_SIZE - 1
+	mov 	eax, [buf]
+	mov 	ecx, eax
+	and 	eax, PAGE_SIZE - 1
 	jnz 	@f
 
 	; is the number of sectors less than or equal to one memory page?
-	cmp 	edx, eax
+	cmp 	edx, ebx
 	jbe 	.success
 	shl 	eax, 1 ; it is page aligned, so set eax to 2 memory pages
 
 @@:
 	; is the number of sectors greater than one or two memory pages?
-	cmp 	edx, eax
+	cmp 	edx, ebx
 	ja 	.build_prp_list
 	
 	; set PRP2
-	mov 	eax, dword [buf]
+	mov 	eax, ecx
 	and 	eax, not (PAGE_SIZE - 1)
 	add 	eax, PAGE_SIZE
 	invoke  GetPhysAddr
@@ -614,40 +614,29 @@ proc alloc_dptr stdcall, ns:dword, prps_ptr:dword, numsectors:dword, prp_list_pt
 	jmp 	.success
 
 .build_prp_list:
-	DEBUGF  DBG_INFO, "Allocating PRP list\n"
-	; allocate PRP list for PRP2
+	xchg 	ecx, ebx
+	and 	ebx, not (PAGE_SIZE - 1)
+	add 	ebx, PAGE_SIZE
 	mov 	eax, [numsectors]
-	mov 	ecx, dword [esi + NSINFO.pg_sectors]
+	mov 	ecx, ebx
 	xor 	edx, edx
 	div 	ecx
-	;test 	edx, edx
-	;jz 	@f
-	;inc 	eax
-	;test 	eax, eax
-	;jz 	@f
-	;dec 	eax
-
-@@:
-	mov 	edx, [buf]
-	and 	edx, not (PAGE_SIZE - 1)
-	add 	edx, PAGE_SIZE
-	stdcall build_prp_list, eax, edx, [prp_list_ptr]
+	stdcall build_prp_list, eax, ebx, [prp_list_ptr]
 	test 	eax, eax
 	jz 	.err
 	mov 	dword [edi + 4], eax
-	jmp 	.success
 	
-.err:
-	xor 	eax, eax
-	pop 	edi esi
-	ret
-
 .success:
 	xor 	eax, eax
 	inc 	eax
-	pop 	edi esi
+	pop 	edi esi ebx
 	ret
 	
+.err:
+	xor 	eax, eax
+	pop 	edi esi ebx
+	ret
+
 endp
 
 nvme_read:
@@ -1120,10 +1109,6 @@ proc nvme_init stdcall, pci:dword
 	jne 	.exit_fail
 
 	mov 	dword [ebx + NSINFO.lbads], eax
-	mov 	eax, PAGE_SIZE
-	mov 	cl, dl
-	shr 	eax, cl
-	mov 	dword [ebx + NSINFO.pg_sectors], eax
 	invoke  KernelFree, edi
 	if 0
 		invoke  KernelAlloc, 0x6000
diff --git a/drivers/nvme/nvme.inc b/drivers/nvme/nvme.inc
index 87e38ab..2c8d4d8 100644
--- a/drivers/nvme/nvme.inc
+++ b/drivers/nvme/nvme.inc
@@ -311,10 +311,9 @@ ends
 struct NSINFO
 	capacity 	dq ?
 	size 	    	dq ?
-	lbads 	    	dd ?
 	nsid 	    	dd ?
-	pg_sectors 	dd ? ; how many sectors equal 1 page?
 	pci 	    	dd ?
+	lbads 	    	db ?
 	features 	db ?
 ends