usermem_6502: add uzero, uputc and uputw

Still need to do uget, uput and ugets

diff --git a/Kernel/usermem_std-6502.s b/Kernel/usermem_std-6502.s
index d14f686..d192dd5 100644 (file)
--- a/Kernel/usermem_std-6502.s
+++ b/Kernel/usermem_std-6502.s
@@ -6,7 +6,8 @@
                .export __uput, __uputc, __uputw, __uzero
 
                .import map_kernel, map_process_always
-
+               .import popax
+               .importzp ptr1, tmp1
 ;
 ;      TO DO: Possibly easier to write them in C with just the _c helpers
 ;      but for speed would be best the block ones are asm.
@@ -38,6 +39,50 @@ __ugetw:     sta ptr1
 
 __ugets:       rts
 __uput:                rts
-__uputc:       rts
-__uputw:       rts
-__uzero:       rts
+
+__uputc:       sta ptr1
+               stx ptr1+1
+               jsr map_process_always
+               jsr popax
+               ldy #0
+               sta (ptr1),y
+               jmp map_kernel
+
+__uputw:       sta ptr1
+               stx ptr1+1
+               jsr map_process_always
+               jsr popax
+               ldy #0
+               sta (ptr1),y
+               txa
+               iny
+               sta (ptr1),y
+               jmp map_kernel
+
+__uzero:       sta tmp1
+               stx tmp1+1
+               jsr map_process_always
+               jsr popax               ; ax is now the usermode address
+               sta ptr1
+               stx ptr1+1
+
+               ldy #0
+               tya
+
+               ldx tmp1+1              ; more than 256 bytes
+               beq __uzero_tail        ; no - just do dribbles
+__uzero_blk:
+               sta (ptr1),y
+               iny
+               bne __uzero_blk
+               inc ptr1+1              ; next 256 bytes
+               dex                     ; are we done with whole blocks ?
+               bne __uzero_blk
+
+__uzero_tail:
+               cpy tmp1
+               beq __uzero_done
+               sta (ptr1),y
+               iny
+               bne __uzero_tail
+__uzero_done:  rts