- /* Initialize the saved register map. When register H is copied to
- register L, we will put H in saved_reg[L]. */
- for (i = 0; i < 16; i++)
- saved_reg[i] = i;
-
- /* Search the prologue looking for instructions that set up the
- frame pointer, adjust the stack pointer, and save registers.
- Do this until all basic prolog instructions are found. */
-
- cache->framesize = 0;
- for (current_pc = prologue_start;
- (current_pc < prologue_end) && ((findmask & 7) != 7);
- current_pc += 2)
- {
- unsigned short insn;
- int regno;
- int offset;
-
- insn = read_memory_unsigned_integer (current_pc, 2);
-
- if ((insn & 0xfe00) == 0xb400) /* push { rlist } */
- {
- int mask;
- findmask |= 1; /* push found */
- /* Bits 0-7 contain a mask for registers R0-R7. Bit 8 says
- whether to save LR (R14). */
- mask = (insn & 0xff) | ((insn & 0x100) << 6);
-
- /* Calculate offsets of saved R0-R7 and LR. */
- for (regno = ARM_LR_REGNUM; regno >= 0; regno--)
- if (mask & (1 << regno))
- {
- cache->framesize += 4;
- cache->saved_regs[saved_reg[regno]].addr = -cache->framesize;
- /* Reset saved register map. */
- saved_reg[regno] = regno;
- }
- }
- else if ((insn & 0xff00) == 0xb000) /* add sp, #simm OR
- sub sp, #simm */
- {
- if ((findmask & 1) == 0) /* before push? */
- continue;
- else
- findmask |= 4; /* add/sub sp found */
-
- offset = (insn & 0x7f) << 2; /* get scaled offset */
- if (insn & 0x80) /* is it signed? (==subtracting) */
- {
- cache->frameoffset += offset;
- offset = -offset;
- }
- cache->framesize -= offset;
- }
- else if ((insn & 0xff00) == 0xaf00) /* add r7, sp, #imm */
- {
- findmask |= 2; /* setting of r7 found */
- cache->framereg = THUMB_FP_REGNUM;
- /* get scaled offset */
- cache->frameoffset = (insn & 0xff) << 2;
- }
- else if (insn == 0x466f) /* mov r7, sp */
- {
- findmask |= 2; /* setting of r7 found */
- cache->framereg = THUMB_FP_REGNUM;
- cache->frameoffset = 0;
- saved_reg[THUMB_FP_REGNUM] = ARM_SP_REGNUM;
- }
- else if ((insn & 0xffc0) == 0x4640) /* mov r0-r7, r8-r15 */
- {
- int lo_reg = insn & 7; /* dest. register (r0-r7) */
- int hi_reg = ((insn >> 3) & 7) + 8; /* source register (r8-15) */
- saved_reg[lo_reg] = hi_reg; /* remember hi reg was saved */
- }
- else
- /* Something in the prolog that we don't care about or some
- instruction from outside the prolog scheduled here for
- optimization. */
- continue;
- }