Changeset 741c0b9 in avrstuff

Timestamp:

Oct 29, 2010, 7:04:18 PM (14 years ago)

Author:

Adrien Destugues <pulkomandy@…>

Branches:

main

Children:

7d5e268

Parents:

53d1ddc

Message:

Some optimizations to get faster interrupts
Some comments in main to tell what it should be doing

git-svn-id: ​svn://pulkomandy.tk/avrstuff@28 c6672c3c-f6b6-47f9-9001-1fd6b12fecbe

File:

• CPC stuff/cpc_serial_2313/code/main.asm (modified) (6 diffs)

CPC stuff/cpc_serial_2313/code/main.asm

@@ -17 +17 @@
 
 .EQU curregbak = SRAM_START
+
+; REGISTERS ALLOCATION
+; R0 = 255 used in interrupt handler for fast switching of DATADIR
+; X (R27 & R26) used in interrupt for fast addressing of regs
 
 .CSEG
@@ -53 +57 @@
 ; We assume X (R26:R27) points to the current reg
 ; So we can load it and react fast enough to the interrupt
-        LDI R16,ALL_OUT ; 1 ; peut être économisé si on sacrifie un reg
-        OUT DATADIR,R0 ; 1
+        OUT DATADIR,R16         ; 1
         LD R27,X                        ; 2 cycles ; peut être économisé si un reg. contient
                                                                         ; déjà la valeur à envoyer
                                                                         ; (mais qui l'update ?)
-        OUT DATAOUT, R27                ; 1 cycle
+        OUT DATAOUT, R27        ; 1 cycle
 
 ; Here data is sent, the CPC read operation is handled.
@@ -68 +71 @@
 
 ; Restore R27
-        LDI R27,curregbak
-        LD R27,X
+        LDS R27,curregbak
 
 ; release the bus
         LDI R16,ALL_IN
         OUT DATADIR, R16
+        LDI R16,ALL_OUT
 
 ; Restore R27 to selected reg. (we erased it to do the OUT)
@@ -82 +85 @@
 cpc_write:
 ; The timing is a bit less constraining here.
-        PUSH R0
-        IN R0,DATAIN
+        PUSH R0                                         ; 2 cycles
+        IN R0,DATAIN                            ; 1
 ; we also need to know A0 state...
-        SBIS CTRLIN,A0
+        SBIS CTRLIN,A0                          ; 1
                 ; This was actually a reg select operation!
                 ; Jump to the proper code
@@ -96 +99 @@
 
 regSel:
-        LDI R27,curregbak
-        ST X,R0
+        STS curregbak,R0
         MOV R27,R0
 
@@ -110 +112 @@
 ; * Set up the INT0 and INT1 so the CPC can do the rest of the setup itself
 init:
-        RJMP init
+        ; setup ctrl port : RW and A0 as inputs, INT as output
+        ; led on (will be turned off by software at init)
+        ; init serial port speed and io
+        ; check for bootloader jumper and jump to bootload code if needed
+
+        SEI
+mainloop:
+        ; maybe we will have to handle a buffer for the serial port
+        ; and 'fake' registers in SRAM
+
+        SLEEP
+        RJMP mainloop