# HG changeset patch
# User Pascal Bellard <pascal.bellard@slitaz.org>
# Date 1683984881 0
# Node ID 82f370bad6b50eaa1086ded0f53ea86c108dc1c7
# Parent  c45b858c787a6a74d83640210847b39b887e3a40
BootProg: fix boot16.asm (again)

diff -r c45b858c787a -r 82f370bad6b5 BootProg/stuff/boot16.asm
--- a/BootProg/stuff/boot16.asm	Sat May 13 11:12:29 2023 +0100
+++ b/BootProg/stuff/boot16.asm	Sat May 13 13:34:41 2023 +0000
@@ -23,7 +23,7 @@
 ;;   and waits for a key to be pressed, then executes the Int 19h           ;;
 ;;   instruction and lets the BIOS continue bootstrap.                      ;;
 ;;                                                                          ;;
-;; - cpu 8086 is supported                                                  ;;
+;; - cpu 8088 is supported                                                  ;;
 ;;                                                                          ;;
 ;;                                                                          ;;
 ;;                             Known Limitation:                            ;;
@@ -31,7 +31,7 @@
 ;; - Need a up to date field bpbHiddenSectors to work in a partition ;      ;;
 ;;   most formatters don't update it correcly in extended partitions.       ;;
 ;;                                                                          ;;
-;; - Partition must fit in the first 8GB disk of the for CHS reads.         ;;
+;; - Partition must fit in the first 8GB of the disk for CHS reads.         ;;
 ;;   (or 2TB for LBA reads).                                                ;;
 ;;                                                                          ;;
 ;;                                                                          ;;
@@ -96,7 +96,7 @@
 NullEntryCheck          equ     1               ; +2 bytes
 ReadRetry               equ     1               ; +9/+13 bytes
 LBAsupport              equ     1               ; +18 bytes
-CHSsanityCheck          equ     1               ; +12/+16 bytes 
+CHSsanityCheck          equ     1               ; +10/+14 bytes 
 GeometryCheck           equ     1               ; +20 bytes
 CheckAttrib             equ     0               ; +6 bytes
 WaitForKey              equ     0               ; +5 bytes
@@ -342,6 +342,9 @@
 FAT16          equ       1
 TINYFAT16      equ       1              ; < 4072 clusters fat16 support
         push    di                      ; up to 2 * 635K / BytesPerCluster = 2540 bytes
+%if FAT12 != 1 && FAT16 != 1
+ %error "FAT12 and/or FAT16 must be set"
+%endif
 %if FAT12 == 1
         mov     cl, 12
 %else
@@ -598,7 +601,6 @@
         dec     bx
         push    di
 %endif
-        mov     si, sp
 
         xchg    ax, cx                  ; save low LBA
         xchg    ax, dx                  ; get high LBA
@@ -606,10 +608,8 @@
         idiv    word [bx(bpbSectorsPerTrack)] ; up to 8GB disks
 
 %if CHSsanityCheck != 0
-        inc     ax
         cmp     ax, [bx(bpbHeadsPerCylinder)]
-        ja      CHSoverflow
-        dec     ax
+        jnc     CHSoverflow
 %endif
         xchg    ax, cx                  ; restore low LBA, save high LBA / SPT
         idiv    word [bx(bpbSectorsPerTrack)]
@@ -632,13 +632,10 @@
                 ; dh = head no.
 
 %if CHSsanityCheck != 0
- %if LBAsupport != 0
-        or      ah, [si+8+3]            ; 8GB max, last cylinder 1023
- %else
-        or      ah, [si+2+3]            ; 8GB max, last cylinder 1023
- %endif
+        sub     ah, 1                   ; set C if cylinder < 1024 (8GB max)
+CHSoverflow:
 %endif
-CHSoverflow:
+        mov     si, sp
 %if CHSsanityCheck != 0 && (ReadRetry != 0 || LBAsupport != 0)
         pushf
 %endif
@@ -651,24 +648,21 @@
         int     13h                     ; extended read sectors (DL, DS:SI)
         jnc     ReadSectorNextSegment
 %endif
+        mov     ax, 201h                ; al = sector count = 1
+                                        ; ah = 2 = read function no.
 %if CHSsanityCheck != 0
  %if ReadRetry != 0 || LBAsupport != 0
         popf
         pushf
  %endif
-        jne     SkipCHS
+        jnc     SkipCHS
 %endif
-
-        mov     ax, 201h                ; al = sector count = 1
-                                        ; ah = 2 = read function no.
         int     13h                     ; read sectors (AL, CX, DX, ES:BX)
-
         jnc     ReadSectorNextSegment
 SkipCHS:
 %if ReadRetry != 0
         cbw                             ; ah = 0 = reset function
         int     13h                     ; reset drive (DL)
-
         dec     di
         jnz     ReadSectorRetry         ; up to 15 extra attempt
 %endif
diff -r c45b858c787a -r 82f370bad6b5 BootProg/stuff/boot32.asm
--- a/BootProg/stuff/boot32.asm	Sat May 13 11:12:29 2023 +0100
+++ b/BootProg/stuff/boot32.asm	Sat May 13 13:34:41 2023 +0000
@@ -90,7 +90,7 @@
 ExtraBootSector         equ     1
 ClusterMask             equ     1               ; +9 bytes
 NullEntryCheck          equ     1               ; +5 bytes
-CheckAttrib             equ     1               ; +6 bytes
+CheckAttrib             equ     0               ; +6 bytes
 NonMirroredFATs         equ     1               ; +20 bytes
 ReadRetry               equ     1               ; +6/7 bytes
 LBA48bits               equ     1               ; +10 bytes
@@ -601,12 +601,12 @@
         jnc     ReadSuccess             ; CF = 0 if no error
 
 %if CHSsupport != 0
+        mov     ax, 201h                ; al = sector count = 1
+                                        ; ah = 2 = read function no.
  %if CHSsanityCheck != 0
         cmp     eax, 0FFFFh             ; max cylinder = 1023
         ja      SkipCHS
  %endif
-        mov     ax, 201h                ; al = sector count = 1
-                                        ; ah = 2 = read function no.
         int     13h                     ; read sectors (AL, CX, DX, ES:BX)
 
         jnc     ReadSuccess             ; CF = 0 if no error