diff options
Diffstat (limited to 'gdb/avr-tdep.c')
| -rw-r--r-- | gdb/avr-tdep.c | 151 |
1 files changed, 110 insertions, 41 deletions
diff --git a/gdb/avr-tdep.c b/gdb/avr-tdep.c index a7ef17c..62f977d 100644 --- a/gdb/avr-tdep.c +++ b/gdb/avr-tdep.c @@ -359,26 +359,81 @@ avr_read_fp (void) 3) the offsets of saved regs This information is stored in the "extra_info" field of the frame_info. - A typical AVR function prologue might look like this: - push rXX - push r28 - push r29 - in r28,__SP_L__ - in r29,__SP_H__ - sbiw r28,<LOCALS_SIZE> - in __tmp_reg__,__SREG__ + Some devices lack the sbiw instruction, so on those replace this: + sbiw r28, XX + with this: + subi r28,lo8(XX) + sbci r29,hi8(XX) + + A typical AVR function prologue with a frame pointer might look like this: + push rXX ; saved regs + ... + push r28 + push r29 + in r28,__SP_L__ + in r29,__SP_H__ + sbiw r28,<LOCALS_SIZE> + in __tmp_reg__,__SREG__ cli - out __SP_L__,r28 - out __SREG__,__tmp_reg__ - out __SP_H__,r29 - - A `-mcall-prologues' prologue look like this: - ldi r26,<LOCALS_SIZE> - ldi r27,<LOCALS_SIZE>/265 - ldi r30,pm_lo8(.L_foo_body) - ldi r31,pm_hi8(.L_foo_body) - rjmp __prologue_saves__+RRR - .L_foo_body: */ + out __SP_L__,r28 + out __SREG__,__tmp_reg__ + out __SP_H__,r29 + + A typical AVR function prologue without a frame pointer might look like + this: + push rXX ; saved regs + ... + + A main function prologue looks like this: + ldi r28,lo8(<RAM_ADDR> - <LOCALS_SIZE>) + ldi r29,hi8(<RAM_ADDR> - <LOCALS_SIZE>) + out __SP_H__,r29 + out __SP_L__,r28 + + A signal handler prologue looks like this: + push __zero_reg__ + push __tmp_reg__ + in __tmp_reg__, __SREG__ + push __tmp_reg__ + clr __zero_reg__ + push rXX ; save registers r18:r27, r30:r31 + ... + push r28 ; save frame pointer + push r29 + in r28, __SP_L__ + in r29, __SP_H__ + sbiw r28, <LOCALS_SIZE> + out __SP_H__, r29 + out __SP_L__, r28 + + A interrupt handler prologue looks like this: + sei + push __zero_reg__ + push __tmp_reg__ + in __tmp_reg__, __SREG__ + push __tmp_reg__ + clr __zero_reg__ + push rXX ; save registers r18:r27, r30:r31 + ... + push r28 ; save frame pointer + push r29 + in r28, __SP_L__ + in r29, __SP_H__ + sbiw r28, <LOCALS_SIZE> + cli + out __SP_H__, r29 + sei + out __SP_L__, r28 + + A `-mcall-prologues' prologue looks like this (Note that the megas use a + jmp instead of a rjmp, thus the prologue is one word larger since jmp is a + 32 bit insn and rjmp is a 16 bit insn): + ldi r26,lo8(<LOCALS_SIZE>) + ldi r27,hi8(<LOCALS_SIZE>) + ldi r30,pm_lo8(.L_foo_body) + ldi r31,pm_hi8(.L_foo_body) + rjmp __prologue_saves__+RRR + .L_foo_body: */ static void avr_scan_prologue (struct frame_info *fi) @@ -457,10 +512,9 @@ avr_scan_prologue (struct frame_info *fi) } } - /* Scanning `-mcall-prologues' prologue - FIXME: mega prologue have a 12 bytes long */ + /* Scanning `-mcall-prologues' prologue */ - while (prologue_len <= 12) /* I'm use while to avoit many goto's */ + while (1) /* Using a while to avoid many goto's */ { int loc_size; int body_addr; @@ -490,9 +544,6 @@ avr_scan_prologue (struct frame_info *fi) break; body_addr |= ((insn & 0xf) | ((insn & 0x0f00) >> 4)) << 8; - if (body_addr != (prologue_start + 10) / 2) - break; - msymbol = lookup_minimal_symbol ("__prologue_saves__", NULL, NULL); if (!msymbol) break; @@ -500,15 +551,33 @@ avr_scan_prologue (struct frame_info *fi) /* FIXME: prologue for mega have a JMP instead of RJMP */ insn = EXTRACT_INSN (&prologue[vpc + 8]); /* rjmp __prologue_saves__+RRR */ - if ((insn & 0xf000) != 0xc000) - break; + if ((insn & 0xf000) == 0xc000) + { + /* Extract PC relative offset from RJMP */ + i = (insn & 0xfff) | (insn & 0x800 ? (-1 ^ 0xfff) : 0); + /* Convert offset to byte addressable mode */ + i *= 2; + /* Destination address */ + i += prologue_start + 10; + + if (body_addr != (prologue_start + 10) / 2) + break; + } + /* jmp __prologue_saves__+RRR */ + else if ((insn & 0xfe0e) == 0x940c) + { + /* Extract absolute PC address from JMP */ + i = (((insn & 0x1) | ((insn & 0x1f0) >> 3) << 16) + | (EXTRACT_INSN (&prologue[vpc + 10]) & 0xffff)); + /* Convert address to byte addressable mode */ + i *= 2; + + if (body_addr != (prologue_start + 12)/2) + break; + } + else + break; - /* Extract PC relative offset from RJMP */ - i = (insn & 0xfff) | (insn & 0x800 ? (-1 ^ 0xfff) : 0); - /* Convert offset to byte addressable mode */ - i *= 2; - /* Destination address */ - i += vpc + prologue_start + 10; /* Resovle offset (in words) from __prologue_saves__ symbol. Which is a pushes count in `-mcall-prologues' mode */ num_pushes = AVR_MAX_PUSHES - (i - SYMBOL_VALUE_ADDRESS (msymbol)) / 2; @@ -606,9 +675,9 @@ avr_scan_prologue (struct frame_info *fi) sbci r29,hi8(XX) in __tmp_reg__,__SREG__ cli - out __SP_L__,r28 + out __SP_H__,r29 out __SREG__,__tmp_reg__ - out __SP_H__,r29 */ + out __SP_L__,r28 */ if (scan_stage == 2 && vpc + 12 <= prologue_len) { @@ -616,19 +685,19 @@ avr_scan_prologue (struct frame_info *fi) unsigned char img[] = { 0x0f, 0xb6, /* in r0,0x3f */ 0xf8, 0x94, /* cli */ - 0xcd, 0xbf, /* out 0x3d,r28 ; SPL */ + 0xde, 0xbf, /* out 0x3e,r29 ; SPH */ 0x0f, 0xbe, /* out 0x3f,r0 ; SREG */ - 0xde, 0xbf /* out 0x3e,r29 ; SPH */ + 0xcd, 0xbf /* out 0x3d,r28 ; SPL */ }; unsigned char img_sig[] = { - 0xcd, 0xbf, /* out 0x3d,r28 ; SPL */ - 0xde, 0xbf /* out 0x3e,r29 ; SPH */ + 0xde, 0xbf, /* out 0x3e,r29 ; SPH */ + 0xcd, 0xbf /* out 0x3d,r28 ; SPL */ }; unsigned char img_int[] = { 0xf8, 0x94, /* cli */ - 0xcd, 0xbf, /* out 0x3d,r28 ; SPL */ + 0xde, 0xbf, /* out 0x3e,r29 ; SPH */ 0x78, 0x94, /* sei */ - 0xde, 0xbf /* out 0x3e,r29 ; SPH */ + 0xcd, 0xbf /* out 0x3d,r28 ; SPL */ }; insn = EXTRACT_INSN (&prologue[vpc]); |