diff options
Diffstat (limited to 'src/txbuf.s')
| -rw-r--r-- | src/txbuf.s | 33 |
1 files changed, 32 insertions, 1 deletions
diff --git a/src/txbuf.s b/src/txbuf.s index dba52c3..6f7b55d 100644 --- a/src/txbuf.s +++ b/src/txbuf.s @@ -6,11 +6,25 @@ tx_buf = $a200 ; MUST agree with src/rxtxbuf.h! - .import _txbuflen + .import _txbuflen, _txbuf_send .export _txbuf_append_chr, _txbuf_append_str .export _txbuf_append_spc, _txbuf_append_01 + .export _txbuf_init, _txbuf_set_str, _txbuf_send_str .importzp sreg ; avoid ptr1 & friends, callers may use +;; void txbuf_init(void) { +;; txbuflen = tx_buf[0] = 0; +;; } +; this asm implementation is the same size as the compiled code, +; but it only uses the Y register, which lets its callers avoid +; having to save the A register before calling it. +_txbuf_init: + ldy #0 + sty tx_buf + sty _txbuflen + sty _txbuflen+1 + rts + _txbuf_append_01: lda #$01 .byte $2c ; BIT abs, skip next instruction @@ -34,6 +48,14 @@ _txbuf_append_chr: ret: rts ; always returns with Y == 0 +;; void txbuf_set_str(const char *str) { +;; txbuf_init(); +;; txbuf_append_str(str); +;; } +_txbuf_set_str: + jsr _txbuf_init ; remember, this doesn't touch A or X! + ; fall through to _txbuf_append_str + ;; void txbuf_append_str(const char *str) { ;; while(*str) { ;; txbuf_append_chr(*str++); @@ -54,3 +76,12 @@ _txbuf_append_str: bne @loop inc sreg+3 bne @loop + rts ; safety net, the above is really a 'branch always' + +;; void txbuf_send_str(const char *str) { +;; txbuf_set_str(str); +;; txbuf_send(); +;; } +_txbuf_send_str: + jsr _txbuf_set_str + jmp _txbuf_send |