From: Will Sowerbutts <will@sowerbutts.com>
Date: Sun, 22 Jan 2017 22:46:29 +0000 (+0000)
Subject: Kernel: zeta-v2: Faster, smaller map_process_2
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=0a9e664b29197b17b2e9843a81eed8845eba407c;p=FUZIX.git

Kernel: zeta-v2: Faster, smaller map_process_2
---

diff --git a/Kernel/platform-zeta-v2/zeta-v2.s b/Kernel/platform-zeta-v2/zeta-v2.s
index 644cc532..18bf3d13 100644
--- a/Kernel/platform-zeta-v2/zeta-v2.s
+++ b/Kernel/platform-zeta-v2/zeta-v2.s
@@ -225,13 +225,6 @@ _program_vectors:
 
 	jr map_kernel
 
-;=========================================================================
-; Memory management
-; - kernel pages:     32 - 34
-; - common page:      35
-; - user space pages: 36 - 63
-;=========================================================================
-
 ;=========================================================================
 ; map_process_always - map process pages
 ; Inputs: page table address in #U_DATA__U_PAGE
@@ -263,31 +256,25 @@ map_kernel:
         jr map_process_2_pophl_ret
 
 ;=========================================================================
-; map_process_2 - map process or kernel pages
+; map_process_2 - map process or kernel pages, update mpgsel_cache
 ; Inputs: page table address in HL
 ; Outputs: none, HL destroyed
 ;=========================================================================
 map_process_2:
-	push de
-	push af
-	ld de,#mpgsel_cache		; paging registers are write only
-					; so cache their content in RAM
-	ld a,(hl)			; memory page number for bank #0
-	ld (de),a
-	out (MPGSEL_0),a		; set bank #0
-	inc hl
-	inc de
-	ld a,(hl)			; memory page number for bank #1
-	ld (de),a
-	out (MPGSEL_1),a		; set bank #1
-	inc hl
-	inc de
-	ld a,(hl)			; memory page number for bank #2
-	ld (de),a
-	out (MPGSEL_2),a		; set bank #2
-	pop af
-	pop de
-	ret
+        push af
+        ld a, (hl)
+        ld (mpgsel_cache+0), a
+        out (MPGSEL_0), a
+        inc hl
+        ld a, (hl)
+        ld (mpgsel_cache+1), a
+        out (MPGSEL_1), a
+        inc hl
+        ld a, (hl)
+        ld (mpgsel_cache+2), a
+        out (MPGSEL_2), a
+        pop af
+        ret
 
 ;=========================================================================
 ; map_restore - restore a saved page mapping