From: Alan Cox <alan@linux.intel.com>
Date: Sat, 3 Jun 2017 21:46:39 +0000 (+0100)
Subject: nc100: first cut at fixing breakage when a read crosses a bank boundary
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=038ec99bb7b294958eff82548a62ea8e617b9b74;p=FUZIX.git

nc100: first cut at fixing breakage when a read crosses a bank boundary
---

diff --git a/Kernel/platform-nc100/devrd.c b/Kernel/platform-nc100/devrd.c
index 305e21b2..fe7b36e5 100644
--- a/Kernel/platform-nc100/devrd.c
+++ b/Kernel/platform-nc100/devrd.c
@@ -29,9 +29,15 @@ static int rd_transfer(bool is_read, uint8_t rawflag)
     dptr = (uint16_t)udata.u_dptr;
 
     while (ct < udata.u_nblock) {
+        uint16_t len;
         /* Pass the page to map for the data */
         map = p[(dptr >> 14)];
-        rd_memcpy(is_read, map, dptr, udata.u_block);
+        len = 0x4000 - (dptr & 0x3FFF);
+        if (len >= BLKSIZE)
+            rd_memcpy(is_read, map, dptr, udata.u_block, BLKSIZE, 0, 0);
+        else
+            rd_memcpy(is_read, map, dptr, udata.u_block, len,
+                p[(dptr >> 14) + 1], BLKSIZE - len);
         udata.u_block++;
         ct++;
         dptr += BLKSIZE;
diff --git a/Kernel/platform-nc100/devrd.h b/Kernel/platform-nc100/devrd.h
index 6320b269..0b8d49a5 100644
--- a/Kernel/platform-nc100/devrd.h
+++ b/Kernel/platform-nc100/devrd.h
@@ -7,7 +7,8 @@ int rd_write(uint8_t minor, uint8_t rawflag, uint8_t flag);
 int rd_open(uint8_t minor, uint16_t flag);
 
 /* asm banking helper */
-void rd_memcpy(uint8_t isread, uint8_t map, uint16_t dptr, uint16_t block);
+void rd_memcpy(uint8_t isread, uint8_t map, uint16_t dptr, uint16_t block,
+                uint16_t len, uint8_t map2, uint16_t len2);
 
 #endif /* __DEVRD_DOT_H__ */
 
diff --git a/Kernel/platform-nc100/nc100.s b/Kernel/platform-nc100/nc100.s
index 72662504..98b4c1fd 100644
--- a/Kernel/platform-nc100/nc100.s
+++ b/Kernel/platform-nc100/nc100.s
@@ -366,12 +366,13 @@ outcharw:
             ret
 
 ;
-; Disk helper  - FIXME should be IRQ safe nowdays
+; Disk helper - FIXME - do we need the di/ei still
 ;
 _rd_memcpy:  push ix
 	    ld ix, #0
 	    add ix, sp
 	    ; 4(ix) = is_read, 5(ix) = dptr page 6-7(ix) = dptr, 8-9(ix) = block
+	    ; 10-11(ix) = len, 12(ix) = map2, 13-14(ix) = len2
             ld l, 6(ix)
 	    ld h, 7(ix)
 	    ld c, 5(ix)
@@ -410,8 +411,24 @@ _rd_memcpy:  push ix
 	    ;
 	    ;	All mapped, and then its simple
 	    ;
-rd_write:   ld bc, #512
+rd_write:   ld c, 10(ix)
+	    ld b, 11(ix)
 	    ldir
+
+	    ld a, 12(ix)		; second page map or 0 = none
+	    or a
+	    jr z, rd_done	; usual case
+	    out (0x12) ,a
+	    ld c, 13(ix)
+	    ld b, 14(ix)
+	    ld a, 4(ix)
+	    or a
+	    jr z, rd_part2
+	    ld hl, #0x8000
+	    jr copy_part2
+rd_part2:   ld de, #0x8000
+copy_part2: ldir
+rd_done:
             call map_kernel	; map the kernel and return
 	    ei
 	    pop ix